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Transfer Case - Isuzu t150 Chevrolet Colorado I

Transfer Case 30 illustrations ~18010 words

Approximate Fluid Capacities

ApplicationSpecification
MetricEnglish
Synchromesh Transmission Fluid GM P/N 12345349 (Canadian P/N 10953465)1.3 liters1.37 quarts

Approximate Fluid Capacities

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
2/4 Indicator Switch39 N.m29 lb ft
Actuator Assembly Bolts22 N.m16 lb ft
Case Half Bolts22 N.m16 lb ft
Detent Plugs19 N.m14 lb ft
Drain Plug39 N.m29 lb ft
Encoder Motor Mounting Bolt22 N.m16 lb ft
Fill Plug39 N.m29 lb ft
NEUTRAL Switch39 N.m29 lb ft
Oil Pump Suction Pipe Bolt15 N.m11 lb ft
Shift Control Module Nut9 N.m80 lb in
Splash Shield Bolts15 N.m11 lb ft
Switch Connector Bracket Bolt15 N.m11 lb ft
Transfer Case Adapter Mounting Bolt50 N.m37 lb ft
Transfer Case Mounting Bolt50 N.m37 lb ft
Transfer Case Shield Bolt20 N.m15 lb ft
Transmission Mount Bolt50 N.m37 lb ft
Vehicle Speed Sensor17 N.m13 lb ft
Vent Baffle Bolt6.5 N.m58 lb in
Yoke Flange Nut137 N.m101 lb ft

Fastener Tightening Specifications

Adhesives, Fluids, Lubricants, and Sealers

ApplicationType of MaterialGM Part Number
United StatesCanada
Detent PlugsPipe Sealant1234600410953480
Oil Pump Suction Pipe BoltThreadlocker1234538210953489
Rear Case Half to Front Case HalfFlange Sealant1237851788900757
Shift Rail Cup PlugsThreadlocker1234538210953489
Splash Shield BoltsThreadlocker1234538210953489
Transfer Case FluidSynchromesh Transmission Fluid1234534910953465
Vent Baffle BoltThreadlocker1234538210953489
Vent PipesRetaining Compound1237790110953504

Adhesives, Fluids, Lubricants, and Sealers

Transfer Case Mechanical Specifications

ApplicationSpecification
MetricEnglish
2/4 Synchronizer Blocking Ring Insert Width9.5-9.7 mm0.374-0.382 in
2/4 Synchronizer Blocking Ring to Gear Clearance1.5 mm - Standard 0.8 mm - Minimum0.059 in - Standard 0.031 in - Minimum
2/4 Synchronizer Blocking Ring to Insert Clearance3.86-4.14 mm - Standard 4.9 mm - Maximum0.152-0.163 in - Standard 0.193 in - Maximum
2/4 Synchronizer Insert to Synchronizer Hub Clearance0.01-0.19 mm - Standard 0.3 mm - Maximum0.0004-0.0075 in - Standard 0.012 in - Maximum
2/4 Wheel Drive Shift Fork9.60-9.85 mm - Standard 9.0 mm - Minimum0.378-0.388 in - Standard 0.354 in - Minimum
Detent Spring Free Length23.4 mm - Standard 23.1 mm - Minimum0.92 in - Standard 0.91 in - Minimum
Detent Spring Tension at Compressed Height7.5-8.5 kg at 18.7 mm16.5-18.7 lb at 0.736 in
High/Low Shift Fork7.60-7.85 mm - Standard 7.0 mm - Minimum0.299-0.309 in - Standard 0.276 in - Minimum
Inner Range Shift Detent Spring Free Length26.6 mm - Standard 25.6 mm - Minimum1.05 in - Standard 1.01 in - Minimum
Inner Range Shift Detent Spring Tension at Compressed Height3.3-4.3 kg @ 18.7 mm7.3-9.5 lb @ 0.736 in

Transfer Case Mechanical Specifications

Scheme 1

Scheme 1: Transfer Case Control Schematics
Scheme 1: Transfer Case Control Schematics

Scheme 2

Scheme 2
Scheme 2

Scheme 3

Scheme 3
Scheme 3

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5: Transfer Case Disassembled View
Scheme 5: Transfer Case Disassembled View
CalloutComponent Name
1Rear Output Shaft Seal
2Rear Bushing
3Rear Case Half
4Vent Hose
5Vent Hose Pipe
6Breather Hose
7Breather Hose Pipe
8Front Case Half
9Input Shaft Seal
10Oil Fill Plug
11Oil Fill Plug Gasket
15Oil Drain Plug
16Oil Drain Plug Gasket
20Front Output Shaft Seal
21Location Pin
21Location Pin
22Front Output Shaft Rear Bearing
23Case Half Bolt
24Shift Shaft Plug
200Actuator Assembly
201Actuator Assembly Bolt
202O2 Sensor Wiring Harness Bracket Bolt
203O2 Sensor Wiring Harness Bracket
204Actuator Assembly O-Ring Seal
205Control Actuator Shaft Seal
206Control Actuator Shaft Bushing
207Shift Shaft Detent Ball
207Shift Shaft Detent Ball
208Shift Shaft Detent Spring
208Shift Shaft Detent Spring
209Shift Shaft Detent Plug
210Shift Shaft Detent Spring
211Shift Shaft Detent Plug
300Vehicle Speed Sensor
301Vehicle Speed Sensor O-Ring Seal
304Breather Baffle Bolt
305Breather Baffle
306Transfer Case NEUTRAL Switch Gasket
307Transfer Case NEUTRAL Switch
310Switch Connector Bracket
311Switch Connector Bracket Bolt
312Front Output Yoke Flange
313Yoke Flange O-Ring Seal
314Yoke Flange Nut
3152/4 Indicator Switch Gasket
3162/4 Indicator Switch
317Oil Deflector Bolt
318Oil Deflector

Scheme 6

Scheme 6
Scheme 6
CalloutComponent Name
100High/Low Planetary Carrier Assembly
101Planetary Carrier Low Gear Retaining Ring
102Planetary Carrier Low Gear
103Rear Output Shaft Front Support Bearing
104Input Shaft Plug
105Input Shaft
106Input Shaft Thrust Bearing
107Pinion Gear Thrust Washer
107Pinion Gear Thrust Washer
108Pinion Gear
109Pinion Gear Bearing
109Pinion Gear Bearing
110Pinion Gear Shaft Spacer
111Pinion Gear Shaft
112Planetary Carrier
113Input Shaft Bearing
114Planetary Carrier Bearing
115Planetary Carrier Bearing Retaining Ring
116Annulus Gear Retaining Ring
117Annulus Gear
118Annulus Gear Dampener
119Carrier Bearing Outer Retaining Ring
120Drive Chain
121Drive Sprocket Retaining Ring
122Drive Sprocket Thrust Washer
123Drive Sprocket
124Rear Output Shaft
125Front Output Shaft Front Bearing
126Front Output Shaft Front Bearing Retaining Ring
127Front Output Shaft
128Rear Output Shaft Retaining Ring
129Speed Sensor Reluctor Wheel
130Rear Output Shaft Bearing
131Rear Output Shaft Bearing Retaining Ring
132Oil Pump Retaining Ring
140Oil Pump Assembly
141Oil Pump Case Screw
142Oil Pump Rear Case
143Oil Pump Gear
144Oil Pump Rotor
145Oil Pump Front Case
146Oil Pump Screen Bolt
147Oil Pump Screen
148Oil Pump Suction Hose Clamp
148Oil Pump Suction Hose Clamp
149Oil Pump Suction Hose
2202/4 Wheel Drive Synchronizer Assembly
221Synchronizer Inner Ring
222Synchronizer Outer Ring
223Synchronizer Blocking Ring
224Synchronizer Sleeve
225Synchronizer Insert Spring
225Synchronizer Insert Spring
226Synchronizer Insert
227Synchronizer Hub
228Synchronizer Assembly Retaining Ring
230High/Low Range Sleeve
2402/4 Wheel Drive Shift Block Pin
2412/4 Wheel Drive Shift Block
2422/4 Wheel Drive Shift Shaft Spring
2432/4 Wheel Drive Shift Fork
2442/4 Wheel Drive Shift Shaft
2452/4 Wheel Drive Shift Fork Retaining Ring
2462/4 Wheel Drive Shift Fork Roller
250High/Low Shift Shaft
251High/Low Shift Fork Retaining Ring
252High/Low Shift Shaft Spring Seat
253High/Low Shift Shaft Spring
254High/Low Shift Block Collar
255High/Low Shift Fork Roller
256High/Low Shift Block
257High/Low Shift Block Retaining Ring
258High/Low Shift Fork
259High/Low Shift Fork Pin
261Control Actuator Shaft
262Control Actuator Cam

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B2725B2725: ATC Mode Switch Circuit Malfunction
DTC C0327C0327: Encoder Circuit Malfunction
DTC C0550C0550: ECU Malfunction

DIAGNOSTIC CODE INDEX

Diagnostic Starting Point - Transfer Case

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check will provide the following information

  1. The identification of the control module or modules that command the system.
  2. The ability of the control module or modules to communicate through the serial data circuit.
  3. The identification of any stored diagnostic trouble codes (DTCs) and the status of the codes.

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

The automatic transfer case (ATC) accessory switch consists of 4 modes. The transfer case shift control module supplies 5 volts to the ATC accessory switch mode buttons. A signal switch low circuit completes the circuit back to the transfer case shift control module. The voltage on the switch signal circuit will vary depending on which button is pressed. When selected, each mode will complete a circuit through their own specific resistor. The transfer case shift control module continuously monitors the switch signal circuit to determine whether the Neutral, 2HI, 4HI, or 4LO mode was selected by the vehicle operator.

Conditions for Running the DTC

  1. The ignition is ON.
  2. The system voltage is 9-16 volts.

Conditions for Setting the DTC

  1. The voltage detected on the switch signal circuit is not within a specified range.
  2. The condition is present for more than 10 seconds.

Action Taken When the DTC Sets

  1. All transfer case shifting is disabled.
  2. The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.
  3. The transfer case defaults to 4WD high mode.

Conditions for Clearing the DTC

  1. The transfer case shift control module will clear the current DTC if the condition for setting the DTC is not currently present.
  2. A history DTC will clear after 100 consecutive ignition cycles without a fault present.
  3. History DTCs can be cleared using a scan tool.

Diagnostic Aids

A low battery condition or charging system that is faulty could set this DTC. Refer to Battery Inspection/Test and Charging System Test .

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, engine OFF, with a scan tool command each mode function switch ON one at a time, on the instrument panel accessory switch. Each mode button indicator light should illuminate.
  2. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records Data.

Circuit/System Testing

IMPORTANTYou must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Ignition OFF, disconnect the accessory switch electrical connector.
  2. Verify that a test lamp illuminates between B+ and terminal H of the accessory switch electrical connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, engine OFF, verify that a test lamp illuminates between terminal A and ground. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal M and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the transfer case shift control module.
  5. Ignition OFF, install a 3 A fused jumper wire between the switch signal low circuit terminal N and the 5-volt reference circuit terminal M at the accessory switch.
  6. Disconnect the transfer case shift control module connector C1.
  7. Ignition ON, verify 4.8-5.2 volts is present at connector C1 terminal 14. If less than the specified range, test the switch signal low circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module. If greater than the specified range, test the switch signal low circuit for a short to voltage. If the circuit tests normal, replace the transfer case shift control module.
  8. If all circuit tests normal, replace the accessory switch.

Component Testing

IMPORTANTYou must perform the Circuit/System Testing before proceeding to Component Testing.
  1. Disconnect the accessory switch electrical connector.
  2. Connect a DMM between the switch signal low circuit and the 5-volt reference circuit at the accessory switch.
  3. Measure the resistance while pressing and holding each of the mode buttons. The resistance values should be within the specified ranges: 4HI: 656.2-669.4 ohms 2HI: 1.50-1.53 K ohms Neutral: 1.010-1.031 K ohms 4LO: 2.32-2.36 K ohms Normal: 9.00-9.18 K ohms
  1. If the resistance values are not within the specified range, replace the accessory switch.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gages)
  2. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for transfer case control module replacement, setup, and programming.
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The transfer case shift control module has 4 encoder circuits, and each circuit is supplied 12 volts. These 4 circuits are A, B, C, and P, and each circuit runs to a switch located inside the encoder/motor assembly. When a particular encoder circuit is active, the switch is closed, and the 12 volts are grounded by the switch inside the encoder. The transfer case shift control module supplies 12 volts on all the circuits. The module can interpret the location of the transfer case shift position when the circuits are grounded.

This DTC detects a fault when it compares the shift sequence/strategy to a chart located in read only memory (ROM) within the transfer case shift control module. This is accomplished by the module reading the different combinations of encoder signals being grounded while others remain high depending on what mode or range the transfer case is in.

  1. The ignition is ON.
  2. The system voltage is 10-16 volts.

This DTC sets when the encoder signals does not match the control strategy contained in the transfer case shift control module.

  1. All motor activity will stop.
  2. All accessory switch mode indicators will be commanded OFF.
  3. The SERVICE 4WD indicator will be on until the fault is corrected.
  4. If a new mode is requested by the driver with either a current or history DTC, the transfer case control module will only allow a shift to 2WD mode. The transfer case control module will not allow further mode changes.
  1. The DTC will set as both current and history.
  2. A scan tool must be used in order to clear a DTC.

A low battery condition or charging system that is faulty could set this DTC. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, engine OFF, command each mode function switch ON one at a time, on the instrument panel accessory switch. Each mode button indicator light should illuminate.
  2. Road test the vehicle in 4LO, 4HI, Neutral, and 2HI. The transfer case should shift into and out of each mode, while operating the vehicle.
  3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records Data.
IMPORTANTYou must perform the Circuit/System Verification before proceeding to Circuit/System Testing.
  1. Ignition OFF, disconnect the transfer case encoder motor electrical connector.
  2. Verify that a test lamp illuminates between B+ and terminal E of the transfer case encoder motor connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, measure for 11-13 volts on terminals A, F, G, H, of the transfer case encoder motor connector. If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the transfer case shift control module.
  4. Ignition OFF, disconnect the transfer case shift control module.
  5. Using a DMM, verify that no continuity is detected between each channel encoder signal circuit. If continuity is detected between the circuits, repair as necessary. If all circuits test normal, replace the transfer case encoder motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Transfer Case Encoder Motor Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  2. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for transfer case shift control module replacement, setup, and programming.
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

At each ignition ON, the transfer case shift control module runs an internal self-test on the following functions

  1. EEPROM Checksum
  2. ROM Checksum
  3. RAM Checksum
  4. RAM Malfunction
  1. The ignition is ON.
  2. The system voltage is between 10-16 volts.
  1. The parameters stored in EEPROM have failed the Checksum test as invalid data.
  2. The parameters stored in ROM have failed the Checksum test as invalid data.
  3. One or more RAM locations have failed operational test indicating that some portions of RAM are not functional.
  1. The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.
  2. Transfer case shifting is disabled.
  1. Replace the transfer case shift control module.
  2. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) .

A low battery condition or charging system that is faulty could set this DTC. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, verify that DTC C0550 is not present.
  2. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the transfer case shift control module electrical connector C1 and C2.
  2. Verify that a test lamp illuminates between B+ and C1 terminal 1. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Verify that a test lamp illuminates between B+ and C1 terminal 9. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Verify that a test lamp illuminates between C1 terminal 8 and ground. If the test lamp does not illuminate test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition ON, verify that a test lamp illuminates between C2 terminal 10 and ground. If the test lamp does not illuminate test the ignition 1 voltage circuit for a short to ground or an open/high resistance.
  6. If all circuits test normal, replace the transfer case shift control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for transfer case shift control module replacement, setup, and programming.

Symptoms - Transfer Case

IMPORTANTPerform the Diagnostic System Check - Vehicle , before using the symptom tables in order to verify that the following statements are true: There are no diagnostic trouble codes (DTCs) set. The control module or modules can communicate via the serial data link. Review the system operation in order to familiarize yourself with the system functions. Refer to Transfer Case Description and Operation .

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the automatic transfer case system. Refer to «Checking Aftermarket Accessories»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  3. Inspect the automatic transfer case for the proper fluid level.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Front Axle Will Not Engage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  2. «Front Axle Will Not Disengage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  3. «Accessory Switch Transfer Case Mode Buttons Inoperative»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  4. «Service Four-Wheel Drive Indicator Always On»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  5. «Service Four-Wheel Drive Indicator Inoperative»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  6. «Accessory Switch Transfer Case Mode Indicator Always On - Two or More»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  7. «Accessory Switch Transfer Case Mode Indicator Flashes, then Returns to Previous Mode»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  8. «Accessory Switch Transfer Case Mode Indicator Inoperative - One or More»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  9. «Accessory Switch Transfer Case Mode Indicator Flashes in 2WD Mode»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  10. «Accessory Switch Transfer Case Mode Indicator Flashes in 4WD High or 4WD Low Mode»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  11. «Accessory Switch Transfer Case Mode Indicator Flashes in 4WD High, 4WD Low, and 2WD Modes»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  12. «Accessory Switch Transfer Case Mode Indicator Flashes in Neutral Mode»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  13. «Transfer Case Popping Noise»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-popping-noise) «Transfer Case Whine or Rumble Noise»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-whine-or-rumble-noise)
  14. «Transfer Case Growl or Grinding Noise»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-growl-or-grinding-noise)
  15. «Transfer Case Clunk in 2HI Only»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-clunk-in-2hi-only)
  16. «Transfer Case Clunk in 4HI»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-clunk-in-4hi)
  17. «Transfer Case Clunk in 4LO»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-clunk-in-4lo)
  18. «Transfer Case Shudder or Binding»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-shudder-or-binding)
  19. «Transfer Case Will Not Shift»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-will-not-shift)
  20. «Transfer Case Jumps Out of Gear»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-jumps-out-of-gear)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit Description

To control the front axle assembly, a front axle actuator will engage or disengage the front axle to transfer case. The front axle actuator motor consists of a permanent magnetic motor, a worm gear controlled plunger, a front axle switch and electronic control circuits all within the actuator assembly.

The front axle actuator consists of the following circuits

  1. An ignition voltage circuit
  2. A ground circuit
  3. The front axle control circuit
  4. The front axle switch circuit

When a shift to 4Hi or 4LO is requested, the transfer case shift control module engages the front axle by grounding the front axle control circuit through a current limiting driver. If the front axle is not able to engage when in 4HI or 4LO, the mode indicator in the switch button will continue to flash.

  1. A mechanical condition inside the front axle could prevent the shift fork from moving, causing the motor to be stuck in one position. Refer to «Symptoms - Front Drive Axle»(/chevrolet/colorado/i-2004-2012/remont/differentials-drive-axles/#front-drive-axle) .
  2. A low battery condition or charging system that is faulty could contribute to the front axle to not engage. Refer to «Battery Inspection/Test»(/chevrolet/colorado/i-2004-2012/remont/charging-system/#battery-charging-system-and-starting-system) and «Charging System Test»(/chevrolet/colorado/i-2004-2012/remont/charging-system/#battery-charging-system-and-starting-system) .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, engine OFF, with a scan tool command the front axle to the Unlocked and Locked positions. The axle should turn ON and OFF with each command.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition OFF, disconnect the front axle actuator electrical connector.
  2. Verify that a test lamp illuminates between B+ and terminal E of the front axle actuator connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between terminals C and E of the front axle actuator connector. If the test lamp does not illuminate test the ignition 1 voltage circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, connect the front axle actuator electrical connector.
  5. Ignition ON, connect a DMM by back probing connector C1 terminal 4 at the transfer case shift control module and ground. The DMM should measure between 10-12 volts. If less than the specified range, test the axle actuator control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the front axle actuator.
  6. Push the 4 HI button on the accessory switch. The DMM display should switch from 10-12 volts to less than 1 volt. If the DMM fails to switch to less than 1 volt, replace the transfer case shift control module.
  7. Ignition OFF for 30 seconds.
  8. Ignition ON, connect a DMM by back probing connector C2 terminal 12 at the transfer case shift control module and ground. The DMM should measure less than 1 volt. If the DMM measures more than 1 volt test the axle switch signal circuit for a short to B+. If the circuit tests normal, replace the front axle actuator.
  9. Push the 4 HI button on the accessory switch. The DMM display should switch from less than 1 volt to 10-12 volts. If the DMM voltage display fails to switch to 10-12 volts, test the axle switch signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the front axle actuator.
  10. If all circuits test normal, replace the transfer case shift control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for transfer case shift control module replacement, setup, and programming.
  2. «Electric Motor Actuator Replacement»(/chevrolet/colorado/i-2004-2012/remont/differentials-drive-axles/#front-drive-axle)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

To control the front axle assembly, a front axle actuator will engage or disengage the front axle to transfer case. The front axle actuator motor consists of a permanent magnetic motor, a worm gear controlled plunger, a front axle switch and electronic control circuits all within the actuator assembly.

The front axle actuator consists of the following circuits

  1. An ignition voltage circuit
  2. A ground circuit
  3. The front axle control circuit
  4. The front axle switch circuit

When a shift to 4Hi or 4LO is requested, the transfer case shift control module engages the front axle by grounding the front axle control circuit through a current limiting driver. If the front axle is not able to engage when in 4HI or 4LO, the mode indicator in the switch button will continue to flash.

  1. A mechanical condition inside the front axle could prevent the shift fork from moving, causing the motor to be stuck in one position. Refer to «Symptoms - Front Drive Axle»(/chevrolet/colorado/i-2004-2012/remont/differentials-drive-axles/#front-drive-axle) .
  2. A low battery condition or charging system that is faulty could contribute to the front axle to not engage. Refer to «Battery Inspection/Test»(/chevrolet/colorado/i-2004-2012/remont/charging-system/#battery-charging-system-and-starting-system) and «Charging System Test»(/chevrolet/colorado/i-2004-2012/remont/charging-system/#battery-charging-system-and-starting-system) .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, engine OFF, with a scan tool command the front axle to the Unlocked and Locked positions. The axle should turn ON and OFF with each command.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition OFF, disconnect the front axle actuator electrical connector.
  2. Verify that a test lamp illuminates between B+ and terminal E of the front axle actuator connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between terminals C and E of the front axle actuator connector. If the test lamp does not illuminate test the ignition 1 voltage circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, connect the front axle actuator electrical connector.
  5. Ignition ON, connect a DMM by back probing connector C1 terminal 4 at the transfer case shift control module and ground. The DMM should measure between 10-12 volts. If less than the specified range, test the axle actuator control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the front axle actuator.
  6. Push the 4 HI button on the accessory switch. The DMM display should switch from 10-12 volts to less than 1 volt. If the DMM fails to switch to less than 1 volt, replace the transfer case shift control module.
  7. Ignition OFF for 30 seconds.
  8. Ignition ON, connect a DMM by back probing connector C2 terminal 12 at the transfer case shift control module and ground. The DMM should measure less than 1 volt. If the DMM measures more than 1 volt test the axle switch signal circuit for a short to B+. If the circuit tests normal, replace the front axle actuator.
  9. Push the 4 HI button on the accessory switch. The DMM display should switch from less than 1 volt to 10-12 volts. If the DMM voltage display fails to switch to 10-12 volts, test the axle switch signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the front axle actuator.
  10. If all circuits test normal, replace the transfer case shift control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for transfer case shift control module replacement, setup, and programming.
  2. «Electric Motor Actuator Replacement»(/chevrolet/colorado/i-2004-2012/remont/differentials-drive-axles/#front-drive-axle)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The accessory switch circuit consists of 4 modes of operation. The transfer case shift control module supplies a 5-volt reference to the accessory switch. A switch signal low circuit completes the path back to the transfer case shift control module. The voltage on the switch signal low circuit will vary depending on which mode button is pressed by the vehicle operator. The transfer case shift control module continuously monitors the switch signal low circuit to determine whether the Neutral, 2HI, 4HI, or 4LO mode was selected.

A low battery condition or charging system that is faulty could contribute to the front axle to not engage. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the accessory switch electrical connector.
  2. Verify that a test lamp illuminates between B+ and terminal H of the accessory switch connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between terminals A and H of the accessory switch connector. If the test lamp does not illuminate test the ignition 1 voltage circuit for a short to ground or an open/high resistance.
  4. Ignition ON, measure for 4.8-5.2 volts at terminal M of the accessory switch connector. If greater than the specified value, test for a short to B+ on the 5-volt reference circuit. If the circuit tests normal, replace the transfer case shift control module. If less than the specified voltage, test for a short to ground or an open/high resistance on the 5-volt reference circuit. If the circuit tests normal, replace the transfer case shift control module.
  5. Ignition OFF, disconnect connector C1 at the transfer case shift control module.
  6. Ignition ON, connect a 3A jumper wire between terminals M and N at the accessory switch connector. Measure for 4.8-5.2 volts at C1 terminal 14 of the transfer case control module. If greater then the specified value, test for a short to B+ on the switch signal low circuit. If the circuits test normal, replace the transfer case shift control module. If less than the specified value, test for a short to ground or an open/high resistance on the switch signal low circuit. If the circuit test normal, replace the transfer case shift control module.
  1. Disconnect the accessory switch electrical connector.
  2. Connect a DMM between terminals M and N on the accessory switch. You should measure the following resistance values while pressing and holding each of the mode buttons: 4HI: 656.2-669.4 ohms 2HI: 1.50-1.53 K ohms Neutral: 1.010-1.031 K ohms 4LO: 2.32-2.36 K ohms Normal: 9.00-9.18 K ohms

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for transfer case shift control module replacement, setup, and programming.
  2. «Electric Motor Actuator Replacement»(/chevrolet/colorado/i-2004-2012/remont/differentials-drive-axles/#front-drive-axle)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The service 4WD indicator is located in the instrument panel cluster (IPC) and shares the common power and ground of the IPC. The transfer case shift control module turns ON or OFF the SERVICE 4WD indicator by sending the IPC a class 2 message.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect connectors C1 and C2 of the transfer case shift control module.
  2. Ignition ON, the Service 4WD indicator on the IPC should be OFF. If the Service 4WD indicator is ON, repair or replace the IPC. If the Service 4WD indicator is OFF, replace the transfer case shift control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for transfer case shift control module replacement, setup, and programming.
  2. «Instrument Cluster Replacement»(/chevrolet/colorado/i-2004-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gages)

The Service 4WD indicator is located in the instrument panel cluster (IPC), and shares the common power and ground of the IPC. The transfer case shift control module controls the service indicator lamp by sending the IPC a Class 2 message. This lamp may be controlled with the scan tool using the IPC device controls.

Test Description

The number below refers to the step number on the diagnostic table.

  1. 2: This step determines if there is a class 2 communication error or if the IPC is faulty.
StepActionYesNo
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Component Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Does any module set a DTC beginning with a 'U'?Go to Scan Tool Does Not Communicate with Class 2 DeviceGo to Step 3
3Replace the instrument panel cluster. Refer to Instrument Cluster Replacement . Did you complete the repair?Go to Step 4
4Use the scan tool in order to clear the DTCs. Operate the vehicle to determine if the symptom has been corrected. Is the symptom still present?Go to Step 1System OK

Service Four-Wheel Drive Indicator Inoperative

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The 4 accessory switch indicator lamps are located on the face of the switch. The 2HI, 4HI, and 4LO indicators are contained inside the respective range button. The Neutral indicator is mounted on the face if the accessory switch. With the ignition ON, the transfer case shift control module grounds the indicator control circuit that corresponds to the selected mode. The transfer case shift control module will flash each indicator lamp after a shift has been requested, and continues to flash until the transfer case shift control module can complete the shift. A 12 volt source located in the accessory switch is applied to the 4 mode indicators.

A low battery condition or charging system that is faulty could produce this fault. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, with a scan tool command all the accessory switch mode indicators OFF. All the mode indicators should turn OFF.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition OFF, disconnect the transfer case shift control module electrical connector.
  2. Ignition ON, all four mode indicator lights on the accessory switch should be OFF. If two or more mode indictor lights are ON, test each indictor control circuit for a short to ground. If the circuit tests normal, replace the transfer case shift control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The transfer case motor is a bi-directional, permanent magnet, D.C. motor. Depending on the command received, the transfer case motor can be energized through either the motor control A or motor control B circuit. The ground circuit for the motor is provided by the motor control circuit that is not energized. The motor, through a series of gears, rotates a shaft which moves the range forks to shift the transfer case between the 2HI, 4HI, 4LO, and Neutral ranges.

A low battery condition or charging system that is faulty could produce this fault. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, with a scan tool command both the motor control A circuit ON and OFF. You should here the encoder motor shifting the transfer case.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition OFF, disconnect the transfer case shift control module electrical connectors C1 and C2.
  2. Verify that a test lamp illuminates between B+ and C1, terminal 1. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Verify that a test lamp illuminates between B+ and C1, terminal 9. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Verify that a test lamp illuminates between C1 terminal 8, and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition ON, verify that a test lamp illuminates between C2 terminal 10 and ground. If the test lamp does not illuminate test the ignition 1 voltage circuit for a short to ground.
  6. Ignition OFF, disconnect the transfer case encoder motor electrical connector.
  7. Verify that a test lamp illuminate between B+ and terminal E of the transfer case encoder motor electrical connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  8. Ignition OFF, connect C1 and C2 to the transfer case shift control module.
  9. Connect a DMM between terminals B and C of the transfer case encoder motor electrical connector.
  10. Ignition ON, with a scan tool, command the motor control A circuit ON and OFF. The DMM should display B+ and zero voltage when commanded ON and OFF. If the DMM displays less than B+ when commanded ON, test both circuits for a short to ground or an open/high resistance. If both circuits test normal, replace the transfer case shift control module.
  11. Ignition OFF, remove the transfer case encoder motor. Inspect the shift detent lever shaft for a binding condition. If the shift detent lever shaft inspection is normal, replace the transfer case encoder motor.
  1. Ignition OFF, disconnect the transfer case shift control module electrical connector.
  2. With a DMM, measure for 2-100 ohms between motor control A and motor control B terminals on the encoder motor. If not with in the specified range, replace the transfer case encoder motor.
  3. Ignition OFF, with a DMM, test for continuity between motor control A terminal and ground, an also motor control B terminal and ground, on the transfer case encoder motor. If continuity is detected, replace the transfer case encoder motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, setup, and programming
  2. «Transfer Case Encoder Motor Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Each mode button and the neutral position on the accessory switch has an indicator. When the ignition is turn ON, all four indicators light simultaneously as an indicator check. With the ignition ON, the transfer case shift control module grounds the indicator control circuit, corresponding to the mode button selected by the vehicle operator. The transfer case shift control module flashes each indicator after a shift has been requested, and continues to flash until the transfer case shift control module completes the shift.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, with a scan tool command all 4 accessory switch indicators ON, one at a time. All 4 indicators should illuminate.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition OFF, disconnect the accessory switch electrical connector.
  2. Verify that a test lamp illuminates between B+ and terminal H of the accessory switch electrical connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between terminals A and H of the accessory switch connector. If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, connect the accessory switch electrical connector.
  5. Ignition OFF, disconnect C1 of the transfer case shift control module.
  6. Ignition ON, with a 3A fused jumper wire, individually ground C1 terminals 10, 11, 12, and 13 one at a time. Each indicator lamp should illuminate when the control circuit is grounded. If the indicator does not illuminate, test the indicator control circuit for an open/high resistance. If the circuit tests normal, replace the accessory switch.
  7. If all circuits test normal, replace the transfer case shift control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, setup, and programming
  2. «Accessory Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gages)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Isuzu T150 transfer case contains a 2/4 wheel indicator switch and a separate neutral switch. Each switch is provided 12 volts on the signal circuit by the transfer case shift control module. A separate ground circuit is provided to both switches. A fault in the 2WD/4WD signal circuit or the neutral switch signal circuit will cause the 2WD mode indicator to flash. Also, a fault in the front axle actuator or actuator circuits can cause the 2WD mode indicator to flash. In 2WD mode, the 2/4 wheel indicator switch and the neutral switch are open and the signal circuits are at B+. In 4WD high, or 4WD low, the transfer case 2/4 wheel indicator switch is closed, and the neutral switch is open.

A low battery condition or charging system that is faulty could produce this fault. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, select the 2WD mode button on the accessory switch. The mode indicator on the 2WD button should be ON steady, after the shift is completed.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition ON, engine OFF. Set the parking brake.
  2. Shift the transfer case to 2WD and the transmission into neutral.
  3. Raise the vehicle on a hoist.
  4. With a scan tool command the front axle actuator to disengage. While spinning a front tire, the front propshaft should not turn. If the front propshaft spins, refer to «Front Axle Will Not Disengage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  5. Ignition OFF, disconnect the transfer case 2/4 wheel indicator switch electrical connector.
  6. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case 2/4 wheel indicator switch connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  7. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 of the transfer case 2/4 wheel indicator switch connector and ground. If the voltage is not within the specified range, test the 2WD/4WD signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
  8. Ignition OFF, disconnect the transfer case neutral switch electrical connector.
  9. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case neutral switch. If the test lamp does not illuminate test the ground circuit for an open/high resistance.
  10. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 on the transfer case neutral switch and ground. If the voltage is not within the specified range, test the neutral switch signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
IMPORTANTYou must perform the Circuit/System Testing first.
  1. Ignition OFF, remove the transfer case 2WD/4WD wheel indicator switch from the transfer case.
  2. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case 2WD/4WD wheel indicator switch.
  3. Remove the transfer case neutral switch from the transfer case.
  4. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case neutral switch.
  5. Test for continuity on the transfer case neutral switch between terminal 1 and the switch housing and also between terminal 2 and the switch housing. If continuity is detected, replace the transfer case neutral switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, setup, and programming
  2. «Transfer Case Neutral Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  3. «Transfer Case 2/4 Indicator Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Isuzu T150 transfer case contains a 2/4 wheel indicator switch and a separate neutral switch. Each switch is provided 12 volts on the signal circuit by the transfer case shift control module. A separate ground circuit is provided to both switches. A fault in the 2WD/4WD signal circuit or the neutral switch signal circuit will cause the 4WD high or 4WD low mode indicator to flash. Also, a fault in the front axle actuator or actuator circuits can cause the 2WD mode indicator to flash. In 2WD mode, the 2/4 wheel indicator switch and the neutral switch are open and the signal circuits are at B+. In 4WD high or low mode, the transfer case 2/4 wheel indicator switch is closed, and the neutral switch is open.

A low battery condition or charging system that is faulty could produce this fault. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, select the 4WD high and low mode button one at a time. The mode indicator on the 4WD high and low button, should be ON steady, after the shift is completed.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition ON, engine OFF. Set the parking brake.
  2. Shift the transfer case to 4WD high and the transmission into neutral.
  3. Raise the vehicle on a hoist.
  4. With a scan tool, command the front axle actuator to engage. While spinning a front tire, the front propshaft should turn. If the front propshaft does not spin, refer to «Front Axle Will Not Engage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  5. Ignition OFF, disconnect the transfer case 2/4 wheel indicator switch electrical connector.
  6. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case 2/4 wheel indicator switch connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  7. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 of the transfer case 2/4 wheel indicator switch connector and ground. If the voltage is not within the specified range, test the 2WD/4WD signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
  8. Ignition OFF, disconnect the transfer case neutral switch electrical connector.
  9. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case neutral switch. If the test lamp does not illuminate test the ground circuit for an open/high resistance.
  10. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 on the transfer case neutral switch and ground. If the voltage is not within the specified range, test the neutral switch signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
IMPORTANTYou must perform the Circuit/System Testing first.
  1. Ignition OFF, remove the transfer case 2WD/4WD wheel indicator switch from the transfer case.
  2. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case 2WD/4WD wheel indicator switch.
  3. Remove the transfer case neutral switch from the transfer case.
  4. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case neutral switch.
  5. Test for continuity on the transfer case neutral switch between terminal 1 and the switch housing and also between terminal 2 and the switch housing. If continuity is detected, replace the transfer case neutral switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, setup, and programming
  2. «Transfer Case Neutral Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  3. «Transfer Case 2/4 Indicator Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Isuzu T150 transfer case contains a 2/4 wheel indicator switch and a separate neutral switch. Each switch is provided 12 volts on the signal circuit by the transfer case shift control module. A separate ground circuit is provided to both switches. A fault in the 2/4 wheel indicator switch signal circuit or the neutral switch signal circuit will cause the 2WD mode indicator to flash. Also, a fault in the front axle actuator or actuator circuits can cause the 2WD mode indicator to flash. In 2WD mode, the 2/4 wheel indicator switch and neutral switch are open and the signal circuits are at B+. In 4WD high, or 4WD low, the transfer case 2/4 wheel indicator switch is closed, and the neutral switch is open.

A low battery condition or charging system that is faulty could produce this fault. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, select the 2WD mode button on the accessory switch. The mode indicator on the 2WD button should be on steady, after the shift is completed.
  2. Ignition ON, select the 4WD high and 4WD low button one at a time. The mode indicator on the 4WD high and 4WD low button should be ON steady, after the shift is completed.
  3. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition ON, engine OFF. Set the parking brake.
  2. Shift the transfer case to 2WD and the transmission into neutral.
  3. Raise the vehicle on a hoist.
  4. With a scan tool command the front axle actuator to disengage. While spinning a front tire, the front propshaft should not turn. If the front propshaft spins, refer to «Front Axle Will Not Disengage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  5. Shift the transfer case to 4WD High.
  6. With a scan tool, command the front axle actuator to engage. While spinning a front tire, the front propshaft should turn. If the front propshaft does not spin, refer to «Front Axle Will Not Engage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  7. Ignition OFF, disconnect the transfer case 2/4 wheel indicator switch electrical connector.
  8. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case 2/4 wheel indicator switch connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  9. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 of the transfer case 2/4 wheel indicator switch connector and ground. If the voltage is not within the specified range, test the 2WD/4WD signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
  10. Ignition OFF, disconnect the transfer case neutral switch electrical connector.
  11. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case neutral switch. If the test lamp does not illuminate test the ground circuit for an open/high resistance.
  12. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 on the transfer case neutral switch and ground. If the voltage is not within the specified range, test the neutral switch signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
IMPORTANTYou must perform the Circuit/System Testing first.
  1. Ignition OFF, remove the transfer case 2/4 wheel indicator switch from the transfer case.
  2. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case 2/4 wheel indicator switch.
  3. Remove the transfer case neutral switch from the transfer case.
  4. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case neutral switch.
  5. Test for continuity on the transfer case neutral switch between terminal 1 and the switch housing, and also between terminal 2 and the switch housing. If continuity is detected, replace the transfer case neutral switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, setup, and programming
  2. «Transfer Case Neutral Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  3. «Transfer Case 2/4 Indicator Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Isuzu T150 transfer case contains a 2/4 wheel indicator switch and a separate neutral switch. Each switch is provided 12 volts on the signal circuit by the transfer case shift control module. A separate ground circuit is provided to both switches. A fault in the 2WD/4WD signal circuit or the neutral switch signal circuit will cause the neutral mode indicator to flash. Also, a fault in the front axle actuator or actuator circuits can cause the neutral mode indicator to flash. In neutral mode, the 2/4 wheel indicator switch is open and the neutral switch is closed. In 4WD high, or 4WD low, the transfer case 2/4 wheel indicator switch is closed, and the neutral switch is open.

A low battery condition or charging system that is faulty could produce this fault. Refer to Battery Inspection/Test and Charging System Test .

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
  2. «Connector Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, select the neutral mode position on the accessory switch. The mode indicator for the neutral position should be ON steady, after the shift is completed.
  2. If the vehicle passes the Circuit/System Verification, then refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/colorado/i-2004-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor) .
  1. Ignition ON, engine OFF. Set the parking brake.
  2. Shift the transfer case to neutral and the transmission into neutral.
  3. Raise the vehicle on a hoist.
  4. Observe the front propshaft when spinning the front tires. The front propshaft should not turn. If the front propshaft spins, refer to «Front Axle Will Not Disengage»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  5. Ignition OFF, disconnect the transfer case 2/4 wheel indicator switch electrical connector.
  6. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case 2/4 wheel indicator switch connector. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  7. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 of the transfer case 2/4 wheel indicator switch connector and ground. If the voltage is not within the specified range, test the 2WD/4WD signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
  8. Ignition OFF, disconnect the transfer case neutral switch electrical connector.
  9. Ignition OFF, verify that a test lamp illuminates between B+ and terminal 2 of the transfer case neutral switch. If the test lamp does not illuminate test the ground circuit for an open/high resistance.
  10. Ignition ON, with a DMM measure for 10-12 volts on terminal 1 on the transfer case neutral switch and ground. If the voltage is not within the specified range, test the neutral switch signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the transfer case shift control module.
IMPORTANTYou must perform the Circuit/System Testing first.
  1. Ignition OFF, remove the transfer case 2WD/4WD wheel indicator switch from the transfer case.
  2. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case 2WD/4WD wheel indicator switch.
  3. Remove the transfer case neutral switch from the transfer case.
  4. Connect a DMM across terminals 1 and 2 on the switch. Measure for less than 1 ohm of resistance with the switch plunger depressed. If the resistance is more than the specified value, replace the transfer case neutral switch.
  5. Test for continuity on the transfer case neutral switch between terminal 1 and the switch housing and also between terminal 2 and the switch housing. If continuity is detected, replace the transfer case neutral switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Transfer Case Neutral Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  2. «Transfer Case 2/4 Indicator Switch Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  3. «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for control module replacement, setup, and programming

Transfer Case Will Not Shift

CauseCorrection
DEFINITION: While shifting from HI range to LO range, there is gear clashing or no HI range; or the transfer case will not shift from 2 wheel drive to 4 wheel drive. Review the Symptoms - Transfer Case and perform the necessary inspections.
Mode shift clashDisassemble the transfer case. Refer to Transfer Case Disassemble . Inspect the synchronizer components for being faulty. Refer to Transfer Case Cleaning and Inspection . Replace the synchronizer, if faulty. Refer to Transfer Case Assemble .
Mode blockDisassemble the transfer case. Refer to Transfer Case Disassemble . Inspect the synchronizer sleeve for sliding freely. Inspect the synchronizer for being faulty. Replace the synchronizer, if faulty. Refer to Transfer Case Assemble .
High/low range shift fork assemblyInspect the high/low shift fork assembly for the following conditions: The roller on the shift block for wear or damage Shift shaft spring broken Worn or melted range fork pads Bent shift shaft Cracked or bent shift fork Refer to Transfer Case Cleaning and Inspection . Replace the high/low shift fork assembly, if found faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
High/low range sleeveInspect the high/low range sleeve for the following conditions: Engagement teeth for burrs or damage Sliding freely on the rear output shaft The range sleeve shift fork collar for excessive wear Refer to Transfer Case Cleaning and Inspection . Replace the range sleeve, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Rear output shaft front support bearingInspect for the following conditions: Failed needle bearing in the input gear Journal on the rear output shaft for excessive wear or damage Refer to Transfer Case Cleaning and Inspection . Replace the bearing, if faulty. Replace the rear output shaft, if damaged.
Planetary carrier low gearInspect the engagement teeth on the planetary carrier low gear for burrs or damage. Refer to Transfer Case Cleaning and Inspection . Replace the planetary carrier low gear, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
2/4 wheel drive shift fork assemblyInspect the 2/4 wheel drive shift fork assembly for the following conditions: The roller on the shift block for wear or damage Shift shaft spring broken Bent shift shaft Worn shift fork pads Cracked or bent shift fork Refer to Transfer Case Cleaning and Inspection . Replace the 2/4 wheel drive shift fork assembly, if found faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Control actuator camInspect for the following conditions: The control actuator cam at the shift fork cams for being worn The bushing for the control actuator cam shaft for being worn Replace the following components, if found faulty: The control actuator cam The bushing for the control actuator shaft Refer to Transfer Case Disassemble and Transfer Case Assemble .
Drive sprocketInspect for the following conditions: Synchronizer engagement teeth on the drive sprocket for burrs or damage Worn bushing in the drive sprocket Journal on the rear output shaft for excessive wear or damage Refer to Transfer Case Cleaning and Inspection . Replace the drive sprocket if it is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the rear output shaft if it is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Will Not Shift

Transfer Case Popping Noise

CauseCorrection
DEFINITION: A faulty internal transfer case component that causes a popping noise in the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Chain jumpReplace the chain and sprockets. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the shaft bearings. Refer to Transfer Case Disassemble and Transfer Case Assemble . Inspect for damaged components caused by metal debris. Refer to Transfer Case Cleaning and Inspection .

Transfer Case Popping Noise

Transfer Case Whine or Rumble Noise

CauseCorrection
DEFINITION: A faulty internal transfer case component that causes a whine or rumbling noise in the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Faulty bearingsInspect all of the bearings and journals. Refer to Transfer Case Cleaning and Inspection . Replace any faulty bearings and any components with faulty bearing journals. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Whine or Rumble Noise

Transfer Case Growl or Grinding Noise

CauseCorrection
DEFINITION: A faulty internal transfer case component that causes a growl or grinding noise in the transfer case while the vehicle is turning or in a 4 wheel drive mode. Review the Symptoms - Transfer Case and perform the necessary inspections.
High/low planetary carrier assemblyInspect the high/low planetary carrier pinion gears for the following conditions: Chipped, bent or deformed teeth Pinion gear bushings worn Pinion gear thrust washers missing Seized or binding pinion gears Refer to Transfer Case Cleaning and Inspection . Replace the high/low planetary carrier assembly if any of the above conditions exist. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Input shaftInspect the input shaft teeth for excessive wear or damage. Refer to Transfer Case Cleaning and Inspection . Replace the input shaft, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Input shaft thrust bearingInspect for a faulty input shaft thrust bearing. Inspect the thrust bearing surfaces for galling. Replace the thrust bearing, if faulty, and the mating component, if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Annulus gearInspect the annulus gear teeth for the following conditions: Damage Chipped teeth Excessive wear Metal embedded in the root of the teeth Refer to Transfer Case Cleaning and Inspection . Replace the annulus gear, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Growl or Grinding Noise

Transfer Case Clunk in 2HI Only

CauseCorrection
DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Incorrect fluid level or incorrect fluidInspect the transfer case for the correct fluid level. Refer to Transfer Case Fluid Replacement . Inspect the transfer case for the correct type of fluid. Flush the transfer case and fill with the correct fluid, if required.
Excessive clearance between the slip yoke and the rear output shaftInspect for the following conditions: Worn slip yoke splines Worn rear output shaft splines Repair or replace the following components, if faulty: Replace the slip yoke. Refer to Front Propeller Shaft Replacement , One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement . Replace the rear output shaft. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Excessive clearance between the slip yoke and the rear bushingInspect for the following conditions: Worn rear bushing Worn slip yoke bushing journal Replace the slip yoke, if required. Refer to Front Propeller Shaft Replacement , One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement . Replace the rear bushing if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Input shaft thrust bearingInspect for worn or missing input shaft thrust bearings. Refer to Transfer Case Cleaning and Inspection . Replace the thrust bearings, as required. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Range sleeveInspect the range sleeve for the following conditions: Worn engagement teeth Worn internal splines Replace the range sleeve, if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Rear output shaft bearing outer retaining ringInspect for the following conditions: Proper installation of the rear output shaft bearing retaining ring Excessive wear or damaged retaining ring groove in the rear case half Repair or replace the following components, if found faulty: Properly install a new rear output shaft bearing outer retaining ring. Replace the rear case half if the retaining ring groove is excessively worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Clunk in 2HI Only

Transfer Case Clunk in 4HI

CauseCorrection
DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in the 4HI range only. Review the Symptoms - Transfer Case and perform the necessary inspections.
Incorrect fluid level or incorrect fluidInspect the transfer case for the correct fluid level. Refer to Transfer Case Fluid Replacement . Inspect the transfer case for the correct type of fluid. Flush the transfer case and fill with the correct fluid, if required. Refer to Transfer Case Fluid Replacement .
Input shaft thrust bearingsInspect for worn or missing input shaft thrust bearings. Refer to Transfer Case Cleaning and Inspection . Replace the thrust bearings, as required. Refer to Transfer Case Disassemble and Transfer Case Assemble .
2/4 Wheel drive synchronizer assemblyInspect the synchronizer for the following conditions: The synchronizer hub for not being press fit on the rear output shaft splines The synchronizer sleeve to the synchronizer hub for wear The synchronizer sleeve to the drive sprocket engagement teeth Refer to Transfer Case Cleaning and Inspection . Replace the synchronizer assembly, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Rear output shaft bearing outer retaining ringInspect for the following conditions: Proper installation of the rear output shaft bearing retaining ring Excessive wear or damaged retaining ring groove in the rear case half Repair or replace the following components, if found faulty: Properly install a new rear output shaft bearing outer retaining ring. Replace the rear case half if the retaining ring groove is excessively worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Range sleeveInspect the range sleeve for the following conditions: Worn engagement teeth Worn internal splines Refer to Transfer Case Cleaning and Inspection . Replace the range sleeve if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Front output shaft yokeInspect the front output shaft yoke for the following conditions: Yoke flange nut loose Yoke loose fit on the front output shaft Replace the yoke flange nut if loose. Refer to Front Output Shaft Seal Replacement . Replace the yoke if the internal splines are worn. Refer to Front Output Shaft Seal Replacement . Replace the front output shaft if the splines are worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Clunk in 4HI

Transfer Case Clunk in 4LO

CauseCorrection
DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in 4LO range only. Review the Symptoms - Transfer Case and perform the necessary inspections.
High/low planetary carrier assemblyInspect for the following conditions: Excessively worn pinion gears The pinion gears loose in the planetary carrier Replace the high/low planetary carrier if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Annulus gearInspect the annulus gear dampener for being faulty. Refer to Transfer Case Cleaning and Inspection . Replace the annulus gear dampener, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble . Inspect the tabs for the annulus gear in the front case for excessive wear. Replace the front case half, if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Range sleeveInspect the range sleeve engagement teeth for excessive wear. Inspect the range sleeve to rear output shaft splines for excessive wear. Replace the range sleeve, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Planetary carrier low gearInspect the fit of the planetary carrier low gear to the planetary carrier for excessive wear. Inspect the engagement teeth of the planetary carrier low gear to the range sleeve for excessive wear. Replace the planetary carrier assembly if the low gear is faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Clunk in 4LO

Transfer Case Shudder or Binding

CauseCorrection
DEFINITION: A shudder, binding, or a crow-hop while turning, which may cause tire scuffing. Review the Symptoms - Transfer Case and perform the necessary inspections.
Rear differentialIf equipped with a G80 axle, flush and fill with the correct fluid. Refer to Locking Rear Drive Axle Chatters in Turns .

Transfer Case Shudder or Binding

Transfer Case Jumps Out of Gear

CauseCorrection
DEFINITION: Loss of the transfer case drive torque during deceleration, acceleration or under load. Review the Symptoms - Transfer Case and perform the necessary inspections.
Faulty high/low range shift forkInspect the high/low range shift fork for being damaged. Refer to Transfer Case Cleaning and Inspection . Replace the shift fork, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Faulty engagement teeth on the range sleeveInspect for the following conditions: The input shaft high speed engagement teeth for wear or damage The engagement teeth on the range sleeve for wear or damage Refer to Transfer Case Cleaning and Inspection . Replace the range sleeve if the teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the input shaft if the input shaft engagement teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
High/low range shift fork block and springInspect the high/low range shift fork spring for being faulty. Inspect the shift block for wear. Refer to Transfer Case Cleaning and Inspection . Replace the high/low range shift fork assembly if the spring or block are faulty. Refer to Transfer Case Assemble .
High/low planetary carrierInspect the high/low planetary carrier for the following conditions: Planetary carrier low gear engagement teeth worn or damaged Cracked carrier housing Pinion gear worn or out of position Pinion gears broken or damaged teeth Pinion gears seized Refer to Transfer Case Cleaning and Inspection . Replace the high/low planetary carrier if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble .
2/4 wheel drive synchronizerInspect the 2/4 wheel drive synchronizer sleeve for worn engagement teeth. Replace the synchronizer, if faulty. Refer to Transfer Case Assemble .
Shift shaft detentsInspect the shift detent springs for being faulty. Refer to Transfer Case Cleaning and Inspection . Inspect the detents on the shift shafts for excessive wear. Refer to Transfer Case Cleaning and Inspection . Replace the detent spring, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the shift shaft, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Jumps Out of Gear

Transfer Case Leak Diagnosis

CauseCorrection
DEFINITION: A visible indication of an external fluid leak from the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Drain plug or fill plug leakInspect the drain or fill plug gasket for being faulty. Install the plugs correctly. Refer to Transfer Case Fluid Replacement .
Hole plug leakingReplace the access hole sealer.
Vehicle speed sensor (VSS) leakingRemove the VSS. Inspect for the following conditions: Cross threaded Cut or damaged O-ring seal VSS over tightened causing deformation in the VSS Refer to Transfer Case Speed Sensor Replacement . Replace the VSS O-ring seal, if faulty. Refer to Transfer Case Speed Sensor Replacement . Replace the VSS, if faulty. Refer to Transfer Case Speed Sensor Replacement .
Rear output shaft seal leakingInspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Seal improperly installed, worn, or damaged Seal bore damaged or cracked Rear output shaft bushing for excessive wear Slip yoke seal surface for wear or pitting Repair or replace the following components, if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Clean or properly route the vent hose. Replace the slip yoke if the surface could cause leakage. Refer to Front Propeller Shaft Replacement , One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement . Replace the rear bushing, if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the rear case half if the seal bore is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the rear output shaft seal. Refer to Rear Output Shaft Seal Replacement .
Front output shaft area leakInspect for the following conditions: Overfilled or improper transfer case fluid Blocked vent Loose yoke flange nut Missing or damaged yoke flange O-ring seal Yoke flange seal surface worn or damaged Seal improperly installed, worn or damaged Seal bore damaged or cracked Repair or replace the following components, if found faulty: Adjust or replace the transfer case fluid. Refer to Transfer Case Fluid Replacement . Clean or properly route the vent hose. Replace the front case half if the seal bore is damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the yoke flange nut and O-ring seal if loose. Refer to Front Output Shaft Seal Replacement . Replace the front output shaft seal. Refer to Front Output Shaft Seal Replacement . Replace the front yoke flange if seal surface is faulty. Refer to Front Output Shaft Seal Replacement .
Control actuator shaft seal leakingReplace the control actuator shaft seal. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Leaking at the vent tubeTransfer case overfilled Inspect for the correct transfer case fluid level. Refer to Transfer Case Fluid Replacement . Replace a damaged or broken vent and seal the vent pipe with the correct sealer. Refer to Transfer Case Assemble .
Leak at transfer case adapter weep hole - automatic transmission onlyInspect for the following conditions: Transmission fluid level low Refer to Transmission Fluid Check and Transfer Case Fluid Replacement . Transmission rear seal for leaking Transfer case input shaft seal for leaking Cup plug in transfer case input shaft for leaking Repair or replace the following components, if found faulty: Replace the transmission rear seal, if leaking. Refer to Propeller Shaft Front Slip Yoke Oil Seal Replacement . Replace the transfer case input shaft seal. Refer to Input Shaft Seal Replacement . Inspect for the following conditions: Seal improperly installed, worn or damaged Seal bore damaged or cracked Input shaft seal surface worn, grooved or damaged Replace the cup plug in the input shaft if leaking. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Leak at transfer case mounting weep hole - manual transmission onlyInspect for the following conditions: Transmission fluid level low Refer to Transmission Fluid Replacement and Transfer Case Fluid Replacement . Transmission rear seal for leaking Transfer case input shaft seal for leaking Cup plug in transfer case input shaft for leaking Repair or replace the following components, if found faulty: Replace the transmission rear seal if leaking. Refer to Transmission Housing Oil Seal Replacement - Rear (RWD) Transmission Housing Oil Seal Replacement - Rear (4WD) . Replace the transfer case input shaft seal if leaking. Refer to Input Shaft Seal Replacement . Inspect for the following conditions: Seal improperly installed, worn, or damaged Seal bore damaged or cracked Input shaft seal surface worn, grooved, or damaged Replace the input shaft if the seal surface is worn. The rear output shaft seal, of the manual transmission, seals on the input shaft of the transfer case. Refer to Transfer Case Disassemble and Transfer Case Assemble . Replace the cup plug in the input shaft, if leaking. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Case leakingInspect for a cracked case or case porosity. Replace the faulty case half. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Front case half to rear case half seam leakDisassemble and seal the case halves. Refer to Transfer Case Assemble .
Switch leaksRemove the NEUTRAL switch or 2/4 indicator switch, if leaking. Inspect for a faulty gasket. Replace the faulty switch gasket. Refer to Transfer Case Neutral Switch Replacement or Transfer Case 2/4 Indicator Switch Replacement .
Shift shaft detent plug leakingInspect the leaking plug for the following conditions: Proper sealant Stripped or damaged threads on the plug or the case. Incorrectly tightened Replace the detent plug, if faulty, and install correctly. Refer to Transfer Case Disassemble and Transfer Case Assemble .
Shift shaft plugs leakingReplace the leaking shift shaft plug. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Transfer Case Leak Diagnosis

Removal Procedure

  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Loosen the transfer case shield bolt (1).
  3. Remove the remaining transfer case shield bolts (2) from the transfer case.
  4. Remove the transfer case shield (3) from the transfer case.

Installation Procedure

  1. Position the transfer case shield (3) to the transfer case and bolt (1).
  2. Install the transfer case shield bolts (2). Tighten: Tighten the transfer case shield bolts to 20 N.m (15 lb ft).
  3. Lower the vehicle.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Clean away all dirt and debris from the transfer case fluid fill and drain plug areas.
  3. Position an appropriate container under the transfer case assembly.
  4. Remove the transfer case fluid fill plug (1) and O-ring gasket.
  5. Remove the transfer case fluid drain plug (2) and O-ring gasket. Allow the transfer case fluid to drain into the container.
  6. Inspect the O-ring gaskets for wear. Replace if necessary.
  1. Install the transfer case fluid drain plug (2) and O-ring gasket. Tighten: Tighten the drain plug to 39 N.m (29 lb ft).
  2. Fill the transfer case to just below the bottom of the fill plug hole with the recommended fluid. Refer to «Approximate Fluid Capacities»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__approximate-fluid-capacities) .
  3. Install the transfer case fluid fill plug (1) and O-ring gasket. Tighten: Tighten the fill plug to 39 N.m (29 lb ft).
  4. Remove the container used to catch the used transfer case fluid from under the vehicle.
  5. Lower the vehicle.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Disconnect the following from the encoder motor (7): The electrical connector (8) The vent hose
  3. Remove the encoder motor mounting bolts.
  4. Remove the encoder motor (3) and O-ring seal (2) from the transfer case. Discard the O-ring seal (2).
IMPORTANTThe actuator shaft in the transfer case may require rotating to the neutral position prior to installing the encoder motor. Do not rotate the actuator shaft using the encoder motor.
  1. Lightly lubricate the NEW O-ring seal (2) with clean transfer case fluid.
  2. Insert the O-ring seal (2) into the transfer case.
  3. Position the encoder motor (3) to the transfer case, aligning the actuator shaft.
  4. Install the encoder motor mounting bolts, with the heated oxygen sensor bracket (1). Tighten: Tighten the encoder motor mounting bolts to 22 N.m (16 lb ft).
  5. Connect the following to the encoder motor (7): The electrical connector (8) The vent hose
  6. Lower the vehicle.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Disconnect the electrical connector (3) from the transfer case speed sensor (2).
  3. Remove the transfer case speed sensor (2) and O-ring seal (1) from the transfer case.
  4. Inspect the O-ring seal (1) for wear. Replace if necessary.
  1. Lightly lubricate the O-ring seal (1).
  2. Position the O-ring seal (1) to the speed sensor (2), if removed.
  3. Install the speed sensor (2) into the transfer case. Tighten: Tighten the speed sensor to 17 N.m (13 lb ft).
  4. Connect the electrical connector (3) to the transfer case speed sensor (2).
  5. Lower the vehicle.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Disconnect the brown engine wiring harness electrical connector (1) from the brown NEUTRAL switch electrical connector (6).
  3. Disconnect the brown NEUTRAL switch electrical connector (2) from the bracket (3).
  4. Remove the transfer case NEUTRAL switch (1) and gasket (4) from the transfer case.
  1. Install the transfer case NEUTRAL switch (1) and gasket (4) into the transfer case. Tighten: Tighten the neutral switch to 39 N.m (29 lb ft).
  2. Connect the brown NEUTRAL switch electrical connector (2) to the bracket (3).
  3. Connect the brown engine wiring harness electrical connector (1) to the brown NEUTRAL switch electrical connector (6).
  4. Lower the vehicle.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Disconnect the gray engine wiring harness electrical connector (2) from the gray 2/4 indicator switch electrical connector (4).
  3. Disconnect the gray 2/4 indicator switch electrical connector (2) from the bracket (1).
  4. Loosen the switch connector bracket bolt in order to release the 2/4 indicator switch pigtail.
  5. Remove the transfer case 2/4 indicator switch (4) and gasket (3) from the transfer case.
  1. Install the transfer case 2/4 indicator switch (4) and gasket (3) into the transfer case. Tighten: Tighten the 2/4 indicator switch to 39 N.m (29 lb ft).
  2. Route the 2/4 indicator switch pigtail along the bracket (1)
  3. Install the switch connector bracket bolt. Tighten: Tighten the switch connector bracket bolt to 15 N.m (11 lb ft).
  4. Connect the gray 2/4 indicator switch electrical connector (2) to the bracket (1).
  5. Connect the gray engine wiring harness electrical connector (2) to the gray 2/4 indicator switch electrical connector (4).
  6. Lower the vehicle.
  1. Remove the drivers bucket seat or split bench seat. Refer to «Front Seat Replacement - Bucket»(/chevrolet/colorado/i-2004-2012/remont/seats/#seat-hardware-seat-trim-and-upholstery) or «Split Bench Seat Replacement»(/chevrolet/colorado/i-2004-2012/remont/seats/#seat-hardware-seat-trim-and-upholstery) .
  2. Remove the left front sill plate. Refer to «Front Side Door Sill Plate Replacement»(/chevrolet/colorado/i-2004-2012/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
  3. Remove the left hinge pillar. Refer to «Body Hinge Pillar Trim Panel Replacement - Left Side»(/chevrolet/colorado/i-2004-2012/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
  4. Remove the left center pillar. Refer to «Center Pillar Lower Trim Panel Replacement»(/chevrolet/colorado/i-2004-2012/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
  5. Use a flat-bladed tool to release the 2 tabs (1) retaining the TCCM to the bracket.
  6. Partially remove the TCCM from the bracket.
  7. Disconnect the electrical connectors.
  8. Remove the TCCM from the vehicle.
  9. If removing the bracket, remove the 2 fasteners retaining the bracket to the floor panel.
  10. Remove the bracket from the vehicle.
  1. If replacing the bracket, install the bracket to the floor panel.
  2. Install the 2 fasteners retaining the bracket to the floor panel. Tighten: Tighten the fasteners to 9 N.m (80 lb in).
  3. Position the TCCM to the bracket.
  4. Connect the electrical connectors.
  5. Install the TCCM to the bracket, ensuring the retaining tabs (1) are fully engaged.
  6. Install the left center pillar. Refer to «Center Pillar Lower Trim Panel Replacement»(/chevrolet/colorado/i-2004-2012/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
  7. Install the left hinge pillar. Refer to «Body Hinge Pillar Trim Panel Replacement - Left Side»(/chevrolet/colorado/i-2004-2012/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
  8. Install the left front sill plate. Refer to «Front Side Door Sill Plate Replacement»(/chevrolet/colorado/i-2004-2012/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
  9. Install the drivers bucket seat or split bench seat. Refer to «Front Seat Replacement - Bucket»(/chevrolet/colorado/i-2004-2012/remont/seats/#seat-hardware-seat-trim-and-upholstery) or «Split Bench Seat Replacement»(/chevrolet/colorado/i-2004-2012/remont/seats/#seat-hardware-seat-trim-and-upholstery) .
  10. Refer to «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for replacement and setup information.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Disconnect the transfer case breather hose (1) from the transfer case vent pipes.
  3. Disconnect the transfer case vent hose (2) from the following: The transfer case vent pipe The encoder motor (3)
  1. Connect the transfer case breather hose (1) to the transfer case vent pipes.
  2. Connect the transfer case vent hose (2) to the following: The transfer case vent pipe The encoder motor (3)
  3. Lower the vehicle.

Front Output Shaft Seal Replacement

Tools Required

  1. J 8614-01 Flange and Pulley Holding Tool
  2. J 37212 Front Output Shaft Seal Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  1. Drain the transfer case fluid. Refer to «Transfer Case Fluid Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150)
  2. Remove the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Using a suitable punch, bend the stakes out on the yoke flange nut.
  4. Using the J 8614-01 to support the flange, loosen the yoke flange nut.
  5. Remove the following: The yoke flange nut The O-ring seal The front output yoke flange Discard the nut and O-ring seal.
  6. Lightly tap a flat bladed screwdriver around the edge of the front output shaft seal.
  7. Pry the front output shaft seal from the transfer case.
  1. Using the J 37212 and a hammer, install the NEW front output shaft seal into the transfer case. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  2. Install the yoke flange to the front output shaft.
  3. Lightly lubricate the NEW yoke flange O-ring seal with transfer case fluid.
  4. Install the yoke flange O-ring seal.
  5. Install a NEW yoke flange nut.
  6. Attach the J 8614-01 to the yoke flange. Tighten: Tighten the yoke flange nut to 137 N.m (101 lb ft).
  7. Using a suitable punch, stake the yoke flange nut in 2 places.
  8. Install the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  9. Fill the transfer case fluid. Refer to «Transfer Case Fluid Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .

Tools Required

J 35582 Oil Pump Seal Installer. See Special Tools .

  1. Remove the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  2. Using a flat-bladed screwdriver and a hammer, remove the rear output shaft seal from the transfer case.
  1. Using the J 35582 and a hammer, install the rear output shaft seal into the transfer case. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  2. Install the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Inspect the transfer case fluid level. Refer to «Transfer Case Fluid Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  1. Drain the transfer case fluid, if necessary. Refer to «Transfer Case Fluid Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  2. Remove the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Remove the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  4. Remove the transfer case encoder motor. Refer to «Transfer Case Encoder Motor Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  5. Disconnect the engine wiring harness electrical connectors (3, 5) from the following: The speed sensor (2) The heated oxygen sensor pigtail
  6. Disconnect the engine wiring harness electrical connectors (1, 2) from the following: The brown NEUTRAL switch electrical connector (6) The gray 2/4 indicator switch electrical connector (4)
  7. Disconnect the engine wiring harness retainers from the transfer case.
  8. Position the engine wiring harness aside.
  9. If equipped with (MA5) complete the following: Remove the transfer case mounting bolts. With the aid of an assistant, carefully lower the transfer case from the vehicle.
  10. If equipped with (M30) complete the following: Remove the transfer case mounting bolts. With the aid of an assistant, carefully lower the transfer case from the vehicle.
  1. If equipped with (M30) complete the following: With the aid of an assistant, carefully raise the transfer case to the transfer case adapter, aligning the splines. NOTE: Refer to «Fastener Notice»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#cautions-and-notices__fastener-notice) . Install the transfer case mounting bolts. Tighten: Tighten the transfer case mounting bolts to 50 N.m (37 lb ft).
  2. If equipped with (MA5) complete the following: Lightly lubricate the transmission rear seal. IMPORTANT: Do not catch the input shaft on the transmission rear seal. With the aid of an assistant, carefully raise the transfer case to the manual transmission, aligning the splines. Install the transfer case mounting bolts. Tighten: Tighten the transfer case mounting bolts to 50 N.m (37 lb ft).
  3. Position the engine wiring harness (3) to the transfer case assembly.
  4. Connect the engine wiring harness retainers to the transfer case.
  5. Connect the engine wiring harness electrical connectors (1, 2) to the following: The brown NEUTRAL switch electrical connector (6) The gray 2/4 indicator switch electrical connector (4)
  6. Connect the engine wiring harness electrical connectors (3, 5) to the following: The speed sensor (2) The heated oxygen sensor pigtail
  7. Install the transfer case encoder motor. Refer to «Transfer Case Encoder Motor Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  8. Install the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  9. Install the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/colorado/i-2004-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  10. Fill the transfer case with fluid, if previously drained. Refer to «Transfer Case Fluid Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .

Input Shaft Seal Replacement

Tools Required

  1. J 3289-20 Holding Fixture
  2. J 23907 Slide Hammer with Bearing Adapter. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  3. J 45278 Seal Remover. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  4. J 45759 Assembly Fixture. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  5. J 45934 Input Seal Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  1. Remove the transfer case assembly. Refer to «Transfer Case Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  2. Install the J 45759 to the transfer case, using 4 suitable bolts. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  3. Mount the J 3289-20 (1) to a sturdy workbench.
  4. Install the J 45759 (2), with the transfer case, into the J 3289-20 (1) and secure with the pivot pin. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  5. Using the J 23907 (1) and J 45278 (2) remove the input shaft seal from the transfer case. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Discard the seal.
  1. Using the J 45934 and a hammer, install the NEW input shaft seal into the transfer case. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . The J 45934 will install the seal to the proper depth. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  2. Remove the J 45759 (2) from the transfer case. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  3. Install the transfer case assembly. Refer to «Transfer Case Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  1. Remove the transfer case assembly. Refer to «Transfer Case Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  2. Remove the 2 transmission mount bolts.
  3. Position a transmission jack under the transmission.
  4. Lift the transmission just high enough to remove the transfer case adapter.
  5. Remove the transfer case adapter mounting bolts.
  6. Remove the transfer case adapter from the transmission.
  7. Remove the transfer case adapter seal.
  1. Lightly lubricate the transfer case adapter seal with clean transmission fluid.
  2. Position the NEW seal to the transfer case adapter.
  3. Install the transfer adapter to the transmission.
  4. Install the transfer case adapter mounting bolts to the transmission. Tighten: Tighten the transfer case adapter mounting bolts to 50 N.m (37 lb ft).
  5. Lower the transmission to the transmission mount.
  6. Install the transmission mount bolts. Tighten: Tighten the transmission mount bolts to 50 N.m (37 lb ft).
  7. Remove the transmission jack.
  8. Install the transfer case assembly. Refer to «Transfer Case Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .

Transfer Case Disassemble

Tools Required

  1. J 3289-20 Holding Fixture
  2. J 8092 Universal Driver
  3. J 8614-01 Flange and Pulley Holding Tool
  4. J 22912-B Rear Pinion and Axle Bearing Remover
  5. J 23907 Slide Hammer with Bearing Adapter. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  6. J 26941 Bushing and Bearing Remover - 3-4 inch. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  7. J 29369-2 Bushing and Bearing Remover - 2-3 inch
  8. J 45278 Seal Remover. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  9. J 45759 Assembly Fixture. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  10. J 45933 Isuzu Transfer Case Assembly/Disassembly Kit. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  11. J 46199 Front Output Shaft Bearing Remover and Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .

Disassemble

  1. Install the J 45759 to the transfer case, using 4 suitable bolts. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  2. Mount the J 3289-20 (1) to a sturdy workbench.
  3. Install the J 45759 (2), with the transfer case, into the J 3289-20 (1) and secure with the pivot pin. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  4. Remove the drain plug (15) and the fill plug (10).
  5. Drain the oil.
  6. Remove the vehicle speed sensor and O-ring seal.
  7. Remove the rear output shaft seal.
  8. Remove the vent hose to the actuator assembly.
  9. Remove the breather hose.
  10. Remove the actuator assembly bolts and wire harness bracket.
  11. Remove the actuator assembly and the O-ring seal.
  12. Remove the wiring harness connectors, for the switches, from the switch connector bracket.
  13. Remove the bolt for the connector bracket.
  14. Remove the connector bracket and spacer.
  15. Remove the 2/4 switch assembly (316) with the copper gasket. The 2/4 switch has the gray wiring harness connector.
  16. Remove the NEUTRAL start switch (307) with the copper gasket. The NEUTRAL start switch has the brown wiring harness connector.
  17. Remove the detent plugs, springs and balls.
  18. Using a suitable punch, bend the stakes out on the yoke flange nut.
  19. Using the J 8614-01 , loosen the yoke flange nut.
  20. Remove the yoke flange nut, the O-ring seal, and the front output yoke flange.
  21. Discard the nut and O-ring seal after removal.
  22. Remove the case half bolts.
  23. Using a soft face hammer on the rear case half, shear the case half sealer.
  24. Using a soft face hammer on the end of the front output shaft, separate the case halves.
  25. Carefully remove the rear case half from the front case half. Only the input shaft, with the planetary carrier assembly, will remain in the front case half.
  26. Remove the high/low shift fork, with the high/low range sleeve and fork, from the output shaft. The 2/4 synchronizer sleeve may have to be moved forward. The roller on the shift fork may fall off because it is not fastened.
  27. Remove the high/low shift fork from the range sleeve.
  28. Remove the 2/4 wheel drive shift fork, and the 2/4 wheel drive synchronizer sleeve. The roller on the shift fork may fall off because it is not fastened.
  29. Remove the shift fork from the sleeve.
  30. Remove the control actuator shaft and the cam.
  31. Remove the 2/4 wheel drive synchronizer inserts from the synchronizer hub.
  32. Remove the bolt retaining the oil pump pick-up tube.
  33. Using snap ring pliers, squeeze together the retaining ring for the rear output shaft rear bearing.
  34. Using a soft face hammer on the rear output shaft, remove the rear output shaft assembly until the rear output shaft bearing is just out of the case.
  35. Remove the front output shaft and the drive chain.
  36. Remove the bolts and the oil deflector.
  37. Remove the rear output shaft assembly completely from the rear case half.
  38. Remove the rear output shaft retaining ring.
  39. Remove the speed sensor reluctor wheel.
  40. Remove the rear output shaft bearing.
  41. Remove the rear output shaft bearing outer retaining ring.
  42. Remove the oil pump assembly with suction hose.
  43. Remove the oil pump suction hose from the oil pump.
  44. Remove the oil pump suction hose from the oil pump screen.
  45. Remove the drive sprocket retaining ring.
  46. Remove the drive sprocket thrust washer.
  47. Remove the drive sprocket.
  48. Remove the synchronizer blocking ring, middle ring and inner ring.
  49. Remove the springs from the synchronizer hub.
  50. Remove the synchronizer hub retaining ring.
  51. Using a hydraulic press and the J 22912-B , remove the synchronizer hub from the rear output shaft.
  52. Remove the rear output shaft front support bearing from inside of the input shaft.
  53. Using the J 23907 (1) and the J 45278 (2), remove the input shaft seal. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . There is not a shoulder to prevent the seal from going into the case. Turn, and hold the J 45278 (2) under the seal for removal. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  54. Using a large pair of snap ring pliers, spread the retaining ring for the planetary carrier bearing.
  55. While the retaining ring is spread, use a soft face hammer on the input shaft to remove the planetary carrier assembly.
  56. For assembly purposes, mark the relationship of the planetary carrier low gear to the planetary carrier.
  57. Remove the retaining ring for the planetary carrier low gear.
  58. Remove the planetary carrier low gear.
  59. Remove the input shaft from the planetary carrier assembly.
  60. Remove the input shaft thrust bearing.
  61. Remove the planetary carrier assembly bearing retaining ring.
  62. Using a hydraulic press with the J 45933-1 (1) of the J 45933 and the J 22912-B (2), remove the planetary carrier bearing. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  63. Using the J 26941 (1) and the J 23907 (2), remove the input shaft bearing from the planetary carrier. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  64. Remove the annulus gear spiral retaining ring.
  65. Remove the annulus gear.
  66. Remove the annulus gear dampener.
  67. Remove the carrier bearing outer retaining ring from the front case.
  68. If necessary, remove the breather baffle and bolt.
  69. Remove the front output shaft front bearing retaining ring.
  70. Remove the front output shaft seal.
  71. Remove the front case half from the J 45759 . See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  72. Inspect the front output shaft bearing for being faulty. Refer to «Transfer Case Cleaning and Inspection»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  73. Using the J 8092 (1) and the J 46199 (2), remove the front output shaft front bearing. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  74. Discard the bearing after removal.
  75. Remove the oil pump retaining ring from the rear case half.
  76. Using the J 23907 (1) and the J 29369-2 (2), remove the front output shaft rear bearing from the rear case half. Do not use the bearing after removal. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  77. Remove the control actuator shaft seal from the rear case.
  78. Inspect the rear bushing for being faulty. Refer to «Transfer Case Cleaning and Inspection»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150) .
  79. If the rear bushing is faulty, remove the bushing using the J 45933-4 (2) and the J 45933-3 (1) of the J 45933 . See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  80. If necessary, remove the shift shaft plugs.
  81. If necessary, remove the vent or breather hose pipes.
  82. If necessary, remove the control actuator shaft bushing.
  83. Disassemble the high/low shift fork by compressing the spring in a vise.
  84. Remove the retaining ring from the shift shaft.
  85. Remove the shift fork assembly from the vise and remove the shift block.
  86. Using a socket and vise, compress the spring in the high/low shift block. Use a small enough diameter socket to allow removal of the inner retaining ring.
  87. Remove the inner retaining ring from the shift block.
  88. Remove the shift block from the vise.
  89. Remove the spring seat (252), the spring (253) and the block collar (254) from the shift block (256).
  90. Remove the roll pin from the high/low shift fork.
  91. Remove the shift fork from the shift shaft.
  92. Disassemble the 2/4 shift fork by compressing the spring in a vise.
  93. Remove the retaining ring from the shift shaft.
  94. Remove the 2/4 shift fork and spring from the shift shaft. The shift block is serviced with the shift shaft.

Front Case Half

  1. Clean the front case half in cleaning solvent and air dry.
  2. Remove the sealer from the case sealing surfaces.
  3. Inspect the case for being broken or cracked.
  4. Inspect the front output shaft front bearing bore (a) for the following conditions: A spun bearing Cracks
  5. Inspect the planetary carrier bearing bore (c) for the following conditions: A spun bearing Cracks
  6. Inspect the case annulus gear notches (b) for wear.
  7. Replace the front case half if any of the above conditions are found.
  8. Inspect the sealing surfaces for damage.
  9. Repair small scratches or nicks with a soft stone.
  10. Inspect the front case to transmission case mounting surface for damage.
  11. Inspect the case threaded bolt holes for damage.
  12. Repair any damaged threads.
  13. Inspect the location pins (21) for being loose or missing.
  14. Repair or replace any damaged location pins.
  15. Inspect the breather pipe and vent hose pipes (5 and 7) for damage or leaking.
  16. Replace the pipes if faulty. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  17. Inspect the control actuator shaft bushing (206) for excessive wear.
  18. Replace the control actuator shaft bushing if faulty. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  19. Inspect the front output shaft front bearing for the following conditions: Roughness Brinelling Pitting
  20. Replace the bearing if any of the above conditions are found. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .

Rear Case Half

  1. Clean the rear case half in cleaning solvent and air dry.
  2. Remove the sealer from the case sealing surfaces.
  3. Inspect the case for being broken or cracked.
  4. Replace the case if it is broken or cracked.
  5. Inspect the sealing surfaces for damage.
  6. Repair small scratches or nicks with a soft stone.
  7. Inspect the case threaded bolt holes for damage.
  8. Repair any damaged threads.
  9. Inspect the front output shaft rear bearing bore (a) for the following conditions: Spun bearing Cracks
  10. Inspect the rear output shaft rear bearing bore (c) for the following conditions: Spun bearing Cracks
  11. Replace the case if the bearing bores are faulty. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  12. Inspect the rear output shaft bushing (2) for scoring or wear.
  13. Replace the bushing if faulty. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  14. Inspect the control actuator shaft bore (b) for the following conditions: Out of round Excessive wear
  15. Replace the case if the control actuator shaft bore is faulty. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  16. Inspect the shift shaft plugs (24) for being loose or leaking.
  17. Replace the shift shaft plugs if leaking. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .

Oil Pump

  1. Remove the oil pump suction hose from the oil pump screen.
  2. Clean the hose and screen in cleaning solvent and air dry.
  3. If the screen is embedded with debris, replace the screen.
  4. Inspect the hose for cracking or tears.
  5. Replace the hose if it is faulty.
  6. Inspect the oil pump for free movement.
  7. Inspect for wear on the oil pump drive teeth.
  8. If there is binding or worn teeth, replace the oil pump. Do not disassemble the oil pump. The oil pump is serviced as a unit.

High/Low Range Components

  1. Clean the annulus gear in cleaning solvent and air dry.
  2. Inspect the annulus gear teeth for the following conditions: Damage or excessive wear Chipped Debris embedded in the root of the teeth
  3. Replace the annulus gear if it is faulty.
  1. Clean the high/low range shift sleeve in cleaning solvent and air dry.
  2. Inspect the high/low range shift sleeve for the following conditions: Excessive wear or roughness on the shift fork pad surface (c) Damaged, chipped or excessively worn engagement teeth (b) Excessively loose or gouged rear output shaft splines (a)
  3. Replace the high/low range shift sleeve if any of the above conditions are found.

High/Low Planetary Carrier Assembly

  1. Clean the high/low planetary carrier (100) and the planetary low gear (102) in cleaning solvent. Do not disassemble the planetary carrier.
  2. Air dry and ensure all cleaning solvent is removed from the bearings in the pinion gears (108). Do not spin the pinion gears with compressed air.
  3. Inspect the pinion gears for chipped teeth.
  4. Inspect the pinion gears for debris embedded in the root of the teeth.
  5. Inspect the pinion gears for excessive side movement from worn bearings or shafts.
  6. Inspect the low range teeth (c) on the planetary low gear (102) for damage or excessive wear.
  7. Inspect the planetary low gear and planetary carrier teeth (b) for excessive wear.
  8. Inspect the thrust washer surface (a) for scoring or excessive wear.
  9. Replace the high/low planetary carrier if any of the above conditions are found. The planetary low gear is serviced only with the planetary carrier assembly.
  10. Inspect the planetary carrier bearing (114), the input shaft bearing (113) and the thrust bearing (106) for the following conditions: Scoring Pitting Brinelling Excessive wear
  11. Replace faulty bearings. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .

Drive Chain and Sprockets

  1. Clean the drive chain (120), the drive sprocket (123) and the front output shaft (127) in cleaning solvent and air dry.
  2. Inspect the drive chain (120) for the following conditions: Loose link pins Binding or stiff links Debris embedded in the links Worn teeth surfaces Stretched chain - interference marks on the case half
  3. Replace the chain if any of the above conditions are found.
  4. Inspect the driven sprocket on the front output shaft (127) and the drive sprocket (123) for the following conditions: Chipped or cracked teeth Excessively worn gear surfaces Slight wear marks are normal. Debris embedded in the root of the teeth
  5. Inspect the drive sprocket (123) for the following conditions: 2/4 Synchronizer engagement teeth for chipping 2/4 Synchronizer engagement teeth for excessive wear
  6. Inspect the drive sprocket bushing for the following conditions: Excessive wear Scoring
  7. Inspect the rear bearing journal on the front output shaft for the following conditions: Scoring Pitting Brinelling Excessive wear
  8. Inspect the threads on the front output shaft for damage.
  9. Inspect the splines on the front output shaft for wear, caused by a loose flange yoke.
  10. Replace the sprockets if any of the above conditions are found. The chain and sprockets may be replaced separately.

Rear Output Shaft

  1. Clean the rear output shaft in cleaning solvent.
  2. Clean the rear output shaft oil galleries and air dry.
  3. Inspect the bearing journals on the rear output shaft for the following conditions: The front support bearing (d) The drive gear bushing (b) Scoring Pitting Brinelling Excessive wear
  4. Inspect the rear output shaft high/low range splines (c) for damage or excessive wear. Witness marks at the location of the gear are normal.
  5. Inspect the rear output shaft splines (a) for wear or damage.
  6. Inspect the rear output shaft bearing area (e) for a spun bearing.
  7. Replace the rear output shaft if any of the above conditions are found.

J 22738-B Valve Spring Tester. See Special Tools .

  1. Clean the following shift system components in cleaning solvent and air dry: The 2/4 synchronizer sleeve (224) The 2/4 shift fork (243) The control actuator shaft (261) The high/low shift fork (258) The control actuator cam (262) The 2/4 synchronizer inserts (226) and springs (225) The 2/4 synchronizer hub (227) The 2/4 synchronizer rings (223, 222 and 221)
  2. Inspect the control actuator cam (262) surfaces for the following conditions: Roughness Grooved Excessive wear
  3. Replace the control actuator cam if faulty.
  4. Inspect the control actuator shaft (261) for the following conditions: Wear at the seal surface Actuator assembly engagement teeth stripped or excessively worn
  5. Replace the control actuator shaft if faulty.
  6. Inspect the 2/4 synchronizer blocking ring (223) for chipped or worn engagement teeth.
  7. Install the 2/4 synchronizer rings on the drive gear.
  8. Using a feeler gage between the blocking ring teeth and the drive gear selector teeth, measure the synchronizer wear. Press down evenly on the rings while measuring. Specification: Standard clearance: 1.5 mm (0.059 in) Minimum clearance: 0.8 mm (0.031 in)
  9. Measure the slots for the inserts, in the blocking ring (223), for wear. Specification: Standard dimension: 9.5-9.7 mm (0.374-0.382 in)
  10. Replace the 2/4 synchronizer rings if they are faulty.
  11. Using a vernier caliper, measure the clearance between the blocking ring and the insert.
  12. If the measured value exceeds the specified limit, the blocking ring and the insert must be replaced. Specification: Standard blocking ring and insert clearance: 3.86-4.14 mm (0.152-0.163 in) Limit blocking ring and insert clearance: 4.9 mm (0.193 in)
  13. Inspect the 2/4 synchronizer hub for the following conditions: Splines (a) press fit to the rear output shaft Steps worn in the sleeve teeth (b)
  14. Install the inserts in the hub slots.
  15. Using a feeler gage, measure for wear. Specification: Standard clearance: 0.01-0.19 mm (0.0004-0.0075 in) Maximum clearance: 0.3 mm (0.012 in)
  16. Inspect the 2/4 synchronizer sleeve for the following conditions: Chipped or worn blocking ring teeth Loose fit to the synchronizer hub caused by excessive wear Shift fork collar surfaces for damage
  17. Inspect the 2/4 synchronizer inserts for excessive wear.
  18. Replace the 2/4 synchronizer assembly if any of the above conditions are found.
  19. Inspect the 2/4 shift shaft for excessive wear at the detent notches.
  20. Inspect the 2/4 shift fork for excessive wear at the synchronizer sleeve surfaces.
  21. Inspect the 2/4 shift fork for cracks or being bent.
  22. Inspect the 2/4 shift fork shaft bore for excessive wear.
  23. Replace any faulty or damaged components. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  24. Inspect the high/low shift shaft for excessive wear at the detent notches.
  25. Inspect the high/low shift block and collars for wear.
  26. Replace any of the above components if they are found faulty. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  27. Measure the sleeve pads on both shift forks for wear. Specification: 2/4 wheel drive shift fork standard thickness: 9.60-9.85 mm (0.378-0.388 in) 2/4 wheel drive shift fork minimum thickness: 9.0 mm (0.354 in) High/Low shift fork standard thickness: 7.60-7.85 mm (0.299-0.309 in) High/Low shift fork minimum thickness: 7.0 mm (0.276 in)
  28. If the measured value is less than the minimum thickness, replace the shift fork. Refer to «Transfer Case Disassemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-disassemble) and «Transfer Case Assemble»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__transfer-case-assemble) .
  29. Inspect the detent springs for distortion or cracks.
  30. Measure the detent spring free length. Specification: Standard length: 23.4 mm (0.92 in) Minimum length: 23.1 mm (0.91 in)
  31. Measure the inner range shift detent spring free length. Specification: Standard length: 26.6 mm (1.05 in) Minimum length: 25.6 mm (1.01 in)
  32. Use J 22738-B or equivalent to measure the detent spring tension. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Specification: Compressed height: 18.7 mm (0.736 in) Standard tension: 7.5-8.5 kg (16.5-18.7 lb)
  33. Use J 22738-B or equivalent to measure the inner range shift detent spring tension. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Specification: Compressed height: 18.7 mm (0.736 in) Standard tension: 3.3-4.3 kg (7.3-9.5 lb)
  34. Replace the detent springs if found faulty.

Transfer Case Assemble

Tools Required

  1. J 3289-20 Holding Fixture
  2. J 8092 Universal Driver
  3. J 8614-01 Flange and Pulley Holding Tool
  4. J 35582 Oil Pump Seal Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  5. J 36371 Output Shaft Bearing Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  6. J 36850 Transjel Lubricant
  7. J 37212 Front Output Shaft Seal Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  8. J 45759 Assembly Fixture. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  9. J 45933 Isuzu Transfer Case Assembly/Disassembly Kit. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  10. J 45934 Input Seal Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  11. J 45936 Control Actuator Shaft Bushing Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  12. J 45937 Rear Output Shaft Retaining Ring Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  13. J 46199 Front Output Shaft Bearing Remover and Installer. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .

Assemble

  1. If disassembled, install the 2/4 shift fork and spring on the shift shaft.
  2. Compress the spring on the 2/4 shift fork in a vise.
  3. Install the retaining ring.
  4. If disassembled, install the high/low shift fork on the shift shaft. Position the fork, as shown, on the shift shaft.
  5. Install the roll pin in the shift fork until flush.
  6. Install the spring seat (252), the spring (253) and the block collar (254) in the shift block (256).
  7. Install the inner retaining ring over a socket.
  8. Install the socket and the block in a vise to compress the spring.
  9. Install the inner retaining ring in the block.
  10. Using a vise, compress the spring in the high/low shift block.
  11. Install the retaining ring on the shift rail.
  12. If removed, using retaining compound GM P/N 12377901 (Canadian P/N 10953504), or equivalent, install the vent or breather hose pipes. Ensure the pipes are properly aligned.
  13. Mount the front case half to the J 45759 with 4 bolts. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  14. Install the J 45759 (2) into the J 3289-20 (1). See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  15. If removed, using the J 45936 , install the control actuator shaft bushing. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  16. If removed, install the breather baffle and bolt. Tighten: Tighten the breather baffle bolt to 6.5 N.m (58 lb in).
  17. Using the J 36371 , install a new front output shaft front bearing in the front case half. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  18. Install a new retaining ring for the front output shaft front bearing.
  19. Install the carrier bearing outer retaining ring in the front case half.
  20. Lubricate the annulus gear dampener with transfer case fluid.
  21. Install the dampener in the case.
  22. Install the annulus gear in the front case. Ensure the dampener is still in the correct position.
  23. Using the J 45933-2 (1) and the J 45933-3 (2) of the J 45933 , compress the dampener under the annulus gear. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Use the J 45933-2 (1) with the step in the annulus gear. Use the J 45933-3 (2) in the bore of the input seal. Compress the dampener until the groove for the annulus retaining ring is exposed.
  24. Install the spiral retaining ring for the annulus gear.
  25. Remove the J 45933 and ensure the spiral retaining ring is fully seated. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  26. Using the J 45933-1 (1) and the J 45933-2 (2) of the J 45933 , install the input shaft bearing in the planetary carrier. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . For ease of installing the bearing, use a vise to hold the nut and the threaded shaft. Stack the J 45933-2 and the planetary carrier over the threaded shaft. In order to install the input shaft bearing at the proper depth, use the side of the J 45933-1 with the step against the bearing.
  27. Using the J 45933-3 (1) and the J 45933-2 (2) of the J 45933 , install the bearing on the planetary carrier. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . The retaining ring groove on the bearing goes toward the planetary carrier. For ease of installing the bearing, use a vise to hold the nut and the threaded shaft. Stack the J 45933-2 and the planetary carrier over the threaded shaft.
  28. Install the planetary carrier bearing retaining ring.
  29. Install the input shaft thrust bearing.
  30. Install the input shaft in the planetary carrier assembly.
  31. If using the planetary carrier and planetary carrier low gear again, align the marks from disassembly.
  32. Install the planetary carrier low gear. The side with the thrust surface faces toward the input shaft.
  33. Install the planetary carrier low gear retaining ring.
  34. Using a large pair of snap ring pliers, spread the carrier bearing retaining ring.
  35. While the retaining ring is spread, install the planetary carrier assembly.
  36. Ensure the retaining ring is secured on the planetary carrier bearing.
  37. Install the rear output shaft front support bearing.
  38. Using J 36850 , pack the bearing.
  39. Using a hydraulic press, install the 2/4 synchronizer hub. The non-shoulder side of the hub aligns to the rear of the rear output shaft. Ensure the hub is supported on the shoulder flange, not on the external hub teeth.
  40. Install the synchronizer hub retaining ring.
  41. Install the rear spring on the synchronizer hub.
  42. Align the spring ends by the insert slots.
  43. Install the front spring, with the ends opposite from the rear spring, on the synchronizer hub.
  44. Align the spring ends by the insert slots.
  45. Install the three synchronizer inserts in the synchronizer hub.
  46. Install the synchronizer sleeve. The sleeve shoulder with the groove aligns forward. Align the flat teeth of the sleeve with the insert. Push in on the inserts.
  47. Install the high/low range sleeve.
  48. Install the high/low shift fork assembly (255) to the high/low range sleeve.
  49. Install the 2/4 shift fork assembly (243) to the 2/4 synchronizer sleeve.
  50. Align the shift blocks as shown.
  51. Lubricate the shift shaft holes in the front case with transfer case fluid.
  52. Install the rear output shaft, with the shift forks, to the front case half. Hold the shift forks in position to the sleeves. Install the shift shafts in the holes in the case. Align the high/low range sleeve teeth with the planetary low gear teeth.
  53. Install the rollers on the shift forks.
  54. Install the control actuator cam. The smaller recess on the cam goes up and faces toward the shift rails.
  55. Rotate the control actuator cam to align to the shift forks.
  56. Install the control actuator shaft. Align the large spline on the shaft with the large groove in the cam.
  57. Install the 2/4 synchronizer blocking ring. Align the tabs on the ring with the insert grooves on the synchronizer hub.
  58. Install the 2/4 synchronizer middle ring.
  59. Install the 2/4 synchronizer inner ring.
  60. Lubricate the journal on the rear output shaft, for the drive sprocket, with transfer case fluid.
  61. With the blue link pointing to the rear case, install the chain on the drive sprocket and the driven sprocket.
  62. Install the chain, the front output shaft and the drive gear.
  63. Rotate the drive gear to align with the tabs on the 2/4 synchronizer rings.
  64. Inspect to ensure the drive gear and the rear output shaft assembly are installed properly. View the chain from the side. The chain links will be parallel to the case sealing flange. If the chain links are not parallel to the case, disassemble until the condition is found.
  65. Install the drive gear thrust washer. Align the thrust washer teeth with the flat area on the rear output shaft.
  66. Select the thickest drive sprocket retaining ring that will fit in the groove. Four sizes are available.
  67. Install the drive sprocket retaining ring.
  68. Measure the retaining ring outside diameter. If the measured diameter is larger than the specified range, use a thinner retaining ring. Specification: Retaining ring outside diameter: 53.0 +/- 0.5 mm (1.969 +/- 0.020 in)
  69. If removed, install the rear bushing in the rear case, using the J 45933-4 (1) and the J 45933-3 (2) of the J 45933 . See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Align the holes of the bushing with the oil grooves in the case. The bushing installed depth is just past the shoulder in the case.
  70. If necessary, install the shift shaft plugs. Use threadlocker GM P/N 12345382 (Canadian P/N 10953489), or equivalent, on the plugs.
  71. Using J 8092 (1) and J 46199 (2), install the front output shaft rear bearing. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . The part numbers on the bearing align away from the case and toward the tool.
  72. Position the speed sensor reluctor wheel in the rear case half, with the oil grooved side toward the inside of the rear case half.
  73. Install the rear output shaft bearing in the rear case half, using the J 45933-3 (1) and the J 45933-1 (2) of the J 45933 . See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Use the single shoulder side of the J 45933-3 in the rear seal bore. Ensure the bearing is being installed square to the bearing bore. Install the bearing until it bottoms in the bearing bore.
  74. Install the rear output shaft bearing retaining ring.
  75. Install the oil pump wire retaining ring, with the ends aligning in the larger open area of the bore.
  76. Prelube the oil pump. Pour a small quantity of transfer case fluid in the oil suction pipe fitting. Rotate the oil pump gear a few turns.
  77. Install the oil pump suction hose to the oil pump.
  78. Install the oil pump suction hose to the oil pump screen.
  79. Install the oil pump, with the screen, in the rear case half. Push on the oil pump and it will snap into position.
  80. Install the oil pump suction tube bolt. Tighten: Tighten the suction tube bolt to 15 N.m (11 lb ft).
  81. Install the oil deflector and bolts. Tighten: Tighten the deflector bolts to 15 N.m (11 lb ft).
  82. Apply a 3 mm (1/8 in) bead of flange sealant GM P/N 12378517 (Canadian P/N 88900757) to the sealing flange on the rear case half. Apply the sealer evenly to the inside surface of the bolt holes, with no gaps.
  83. If necessary, install the locating pins in the front case half.
  84. Install the rear case half. Rotate the input shaft to allow the rear output shaft to align with the speed sensor reluctor wheel splines. Lightly tap down on the rear case half to fully install on the locating pins.
  85. Install the case half bolts. Tighten: Tighten the case half bolts to 22 N.m (16 lb ft).
  86. Position a new rear output shaft retaining ring over the rear output shaft.
  87. Using the J 45937 , install the retaining ring. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) . Tap lightly, or use hand pressure on the J 45937 until the retaining ring installs in the groove. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  88. Using the J 35582 with a hammer, install the rear output shaft seal. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  89. Install the control actuator shaft seal flush to the case surface. The spring side installs to the inside.
  90. Using the J 45934 with a hammer, install the input shaft seal. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  91. Using the J 37212 with a hammer, install the front output shaft seal. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .
  92. Install the detent springs and balls.
  93. Apply GM P/N 12346004 (Canadian P/N 10953480) to the threads on the detent plugs.
  94. Install the detent plugs. Tighten: Tighten the detent plugs to 19 N.m (14 lb ft).
  95. Install the yoke flange on the front output shaft.
  96. Lightly lubricate a new yoke flange O-ring with transfer case fluid.
  97. Install the yoke flange O-ring.
  98. Install a new yoke flange nut.
  99. Install the J 8614-01 to assist in tightening the yoke flange nut. Tighten: Tighten the yoke flange nut to 137 N.m (101 lb ft).
  100. Remove the J 8614-01 .
  101. Using a suitable punch, stake the yoke flange nut in 2 places.
  102. Install the 2/4 switch assembly (316) with the copper gasket. The 2/4 switch has the gray wiring harness connector. Tighten: Tighten the 2/4 switch to 39 N.m (29 lb ft).
  103. Install the NEUTRAL start switch (307) with the copper gasket. The NEUTRAL start switch has the brown wiring harness connector. Tighten: Tighten the NEUTRAL switch to 39 N.m (29 lb ft).
  104. Install the switch connector bracket and spacer.
  105. Install the connector bracket bolt. Tighten: Tighten the connector bracket bolt to 15 N.m (11 lb ft).
  106. Install the wiring harness connectors, for the switches, into the switch connector bracket.
  107. Install the actuator assembly and the new O-ring seal.
  108. Install the actuator assembly bolts and wire harness bracket. Tighten: Tighten the actuator assembly bolts to 22 N.m (16 lb ft).
  109. Install the vent hose to the actuator assembly.
  110. Install the breather hose.
  111. Install the vehicle speed sensor (VSS) and O-ring seal. Tighten: Tighten the VSS to 17 N.m (13 lb ft).
  112. Install a new O-ring gasket on the drain plug and the fill plug.
  113. Install the drain plug (15) and the fill plug (10). Tighten: Tighten the drain plug and fill plug to 39 N.m (29 lb ft).
  114. Remove the transfer case from the J 3289-20 .
  115. Remove the J 45759 from the transfer case. See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/transfer-case/#transfer-case-isuzu-t150__special-tools) .

Scheme 7

Scheme 7: General Description
Scheme 7: General Description
IMPORTANTTo reduce range shift clunk noise while shifting, the transfer case has had design improvements over this model year to include an additional spring to the high/low shift shaft detent. This spring nests inside the existing spring and provides increased pressure on the detent ball; this increased pressure allows longer windup time for the spring in the actuator, therefore, allowing the shift to occur faster, reducing range shift clunk noise. Depending on the design level, this transfer case may or may not have this additional spring.

The Isuzu T150 transfer case is a 2 speed, part time 4WD with electric shift. A high/low planetary carrier assembly (100) provides the high and low ranges. The arrangement of the high/low planetary carrier assembly, which includes the 4 pinion gears (108), the sun gear - the outer teeth on the input shaft (105), and the annulus gear (117), gives a 2.48 low range reduction ratio. Using a synchronizer (220), the T150 provides the 4WD mode by connecting the drive sprocket (123) to the rear output shaft (124). The front output shaft (127) is chain (120) driven from the drive sprocket (123). The transfer case uses two shift shafts (250) operated by a single cam (262). The actuator assembly (200) rotates the cam (262) to the various ranges or modes. Detent springs (208) and balls (207) hold the shift shafts (250) in position.

The T150 case halves are cast aluminum. A needle bearing (113), in the planetary carrier assembly (100), supports the input shaft (105). A ball bearing (114), located in the front case half, supports the planetary carrier assembly (100). A needle bearing (103) is located inside the input shaft (105), to support the front of the rear output shaft (124). The rear output shaft (124) is supported at the rear by a ball bearing (130), located in the rear case half. The transfer case uses Synchromesh Transmission Fluid GM P/N 12345349 (Canadian P/N 10953465) as a service fluid. An oil pump (140) pumps the fluid through the oil gallery, in the rear output shaft, to the gears and bearings.

Scheme 8

Scheme 8: 2HI to 4HI Power Flow
Scheme 8: 2HI to 4HI Power Flow

During operation in 2HI mode, the input shaft (105) delivers the engine power from the transmission. The high/low range sleeve (230) connects the input shaft (105), to the rear output shaft (124). The high/low range sleeve (230) outer teeth engage with the input shaft (105) inner teeth, which are the high-speed teeth. The high/low range sleeve (230) is slip splined to the rear output shaft (124). The rear output shaft (124) delivers the engine power to the rear propeller shaft.

When commanding the transfer case to 4HI mode, the actuator assembly (200) rotates the control actuator cam (262). The control actuator cam (262) moves the 2/4 wheel drive shift fork (243) rearward. The 2/4 wheel drive shift fork (243) moves the synchronizer sleeve (224) of the 2/4 wheel drive synchronizer (220), to the blocking rings (223). The blocking rings (223) brake the drive sprocket (123) to match the revolutions of the rear output shaft (124). Matching the revolutions, the synchronizer sleeve (224) engages the synchronizer hub (227) to synchronizer blocking rings (223), which are connected to the drive sprocket (123). The synchronizer hub (227) is pressed fit on the rear output shaft (124). The engine power now flows through the synchronizer assembly (220) to the drive sprocket (123). A chain (120) connects the drive sprocket to the driven sprocket on the front output shaft (127), delivering the engine power now to both the front propeller shaft and the rear propeller shaft.

Scheme 9

Scheme 9: 4LO Power Flow
Scheme 9: 4LO Power Flow

When shifting the transfer case to 4LO range, it commands the actuator assembly (200) to rotate the control actuator cam (262). The control actuator cam (262) shifts the high/low range sleeve (230) to low range, while keeping the 2/4 wheel drive synchronizer (220) engaged in the 4WD position.

The high/low shift fork (258) moves the high/low range sleeve (230) rearward. The high/low range sleeve (230) outer teeth disconnect from the high-speed teeth on the input shaft (105). The high/low range sleeve (230) outer teeth now engage with the low range gear (102). The low range gear (102) is tooth to the planetary carrier (112).

The outer teeth, or low range teeth, on the input shaft (105), which now acts like a sun gear, delivers the engine power to the pinion gears (108) in the planetary carrier (112). Rotating the pinion gears (108), which are engaged in the annulus gear (117), rotates the planetary carrier (112). The planetary carrier (112) delivers the power to the high/low range sleeve (230). The high/low range sleeve (230) then drives the rear output shaft (124), providing a 2.48:1 reduction to the speed of the rear output shaft (124). The 2/4 wheel drive synchronizer is still engaged, and engine torque is delivered to front and rear propeller shafts.

Scheme 10

Scheme 10: Accessory Switch
Scheme 10: Accessory Switch

The Isuzu T150 transfer case features a 3-button accessory switch located on the instrument panel. When the vehicle has the ignition key in the RUN position, the transfer case shift control module starts monitoring the accessory switch to determine if the driver desires a new mode/range position. At a single press of the accessory switch, the lamp of the new desired position will begin flashing to inform the driver that the transfer case shift control module has received the request for a new mode/range position. The lamp will continue to flash until all shifting criteria have been met and the new mode/range position has been reached, or has been engaged. Once the new mode/range position is fully active, the switch indicator lamp for the new position will remain ON constantly.

During normal driving situations, the transfer case operates in the 2HI mode. When the 2HI mode is selected, the transfer case shift control module sends 12 volts to an electrical motor, which is the transfer case encoder motor. This motor rotates the transfer case shift detent lever shaft which moves the shift forks and range sleeve to obtain different modes/ranges.

The Isuzu T150 transfer case has the added feature of also providing the driver with 2 selectable mode/range positions

  1. 2HI
  2. 4HI
  3. 4LO

The transfer case does not allow a shift into or out of 4LO unless the following criteria is met

  1. The engine is running.
  2. The automatic transmission is in NEUTRAL.
  3. The vehicle speed is less than 5 km/h (3 mph).

This transfer case also has a NEUTRAL position. A shift to the NEUTRAL position allows the vehicle to be towed without the transmission output shaft rotating. Refer to the Owner's Manual for instructions for proper towing of the vehicle.

NEUTRAL position is obtained only if the following criteria is met

  1. The ignition is ON.
  2. The automatic transmission is in NEUTRAL.
  3. The vehicle speed is less than 5 km/h (3 mph).
  4. The transfer case is in the 2HI mode.

Once these conditions have been met, press and hold both the 2HI and 4LO Lock buttons for 10 seconds. When the system completes the shift to NEUTRAL, the red NEUTRAL indicator will illuminate.

Transfer Case Electrical Component Description

The following list of major electrical components make up the four wheel drive transfer case system.

Service 4WD Indicator

The SERVICE 4WD indicator is an integral part of the cluster and cannot be serviced separately. This indicator is used to inform the driver of the vehicle of malfunctions within the four wheel drive transfer case system. The SERVICE 4WD indicator is controlled by the transfer case shift control module via a Class 2 message.

Transfer Case Encoder

The encoder is mounted to the transfer case encoder motor assembly and is replaced only as an assembly. The encoder converts the shift detent lever shaft position, representing a mode/range into electrical signal inputs to the transfer case shift control module. The module detects what position the transfer case is in by monitoring the 4 encoder channels, P, B, A, and C. These inputs translate into 2HI, 4HI, 4LO, and NEUTRAL, or whether the motor is still in transition between gears.

Scheme 11

Scheme 11: Transfer Case Encoder Motor
Scheme 11: Transfer Case Encoder Motor

The transfer case encoder motor consists of a permanent magnet (PM) DC motor and gear reduction assembly. It is located on the left hand side of the transfer case. When activated, it turns the shift detent lever shaft of the transfer case clockwise or counterclockwise, to shift the transfer case by moving the shift forks and collar assemblies inside the transfer case. The encoder motor is controlled through a 12 volt circuit provided by the transfer case shift control module. This circuit consists of a driver on both the motor control A and motor control B circuits. The encoder motor is bi-directional to allow the motor to shift the transfer case from 2HI to 4HI to NEUTRAL and 4LO positions.

Scheme 12

Scheme 12: Transfer Case Shift Control Module
Scheme 12: Transfer Case Shift Control Module

The transfer case shift control module monitors vehicle speed via the class 2 data bus from the powertrain control module as well as controlling the operation of the transfer case encoder motor assembly.

Special Tools

Special Tools Illustration Tool Number/Description J 3289-20 Holding Fixture J 8092 Universal Driver J 8614-01 Flange and Pulley Holding Tool J 22738-B Valve Spring Tester J 22912-B Rear Pinion and Axle Bearing Remover J 23907 Slide Hammer with Bearing Adapter J 26941 Bushing and Bearing Remover - 3-4 inch J 29369-2 Bushing and Bearing Remover - 2-3 inch J 35582 Oil Pump Seal Installer J 36371 Output Shaft Bearing Installer J 36850 Transjel Lubricant J 37212 Front Output Shaft Seal Installer J 45278 Seal Remover J 45759 Assembly Fixture J 45933 Isuzu Transfer Case Assembly/Disassembly Kit J 45934 Input Seal Installer J 45936 Control Actuator Shaft Bushing Installer J 45937 Rear Output Shaft Retaining Ring Installer J 46199 Front Output Shaft Bearing Remover and Installer

Scheme 13

Scheme 13: Special Tools
Scheme 13: Special Tools

Scheme 14

Scheme 14
Scheme 14

Scheme 15

Scheme 15
Scheme 15

Scheme 16

Scheme 16
Scheme 16

Scheme 17

Scheme 17
Scheme 17

Scheme 18

Scheme 18
Scheme 18

Scheme 19

Scheme 19
Scheme 19

Scheme 20

Scheme 20
Scheme 20

Scheme 21

Scheme 21
Scheme 21

Scheme 22

Scheme 22
Scheme 22

Scheme 23

Scheme 23
Scheme 23

Scheme 24

Scheme 24
Scheme 24

Scheme 25

Scheme 25
Scheme 25

Scheme 26

Scheme 26
Scheme 26

Scheme 27

Scheme 27
Scheme 27

Scheme 28

Scheme 28
Scheme 28

Scheme 29

Scheme 29
Scheme 29

Scheme 30

Scheme 30
Scheme 30

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Battery Inspection/Test
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Powertrain Diagnostic Trouble Code (DTC) Type Definitions
• Control Module References
• Diagnostic Repair Verification
• Accessory Switch Replacement
• Checking Aftermarket Accessories
• Symptoms - Front Drive Axle
• Scan Tool Does Not Communicate with Class 2 Device
• Front Propeller Shaft Replacement
• Locking Rear Drive Axle Chatters in Turns
• Transmission Fluid Check
• Propeller Shaft Front Slip Yoke Oil Seal Replacement
• Transmission Fluid Replacement
• Transmission Housing Oil Seal Replacement - Rear (4WD)
• Lifting and Jacking the Vehicle
• Fastener Notice
• Component Fastener Tightening Notice
• Front Seat Replacement - Bucket
• Front Side Door Sill Plate Replacement
• Transfer Case Seal Removal Notice
• Machined Surface Damage Notice
• DTC B2725
• Transfer Case Popping Noise
• Transfer Case Whine or Rumble Noise
• Transfer Case Growl or Grinding Noise
• Transfer Case Clunk in 2HI Only
• Transfer Case Clunk in 4HI
• Transfer Case Clunk in 4LO
• Transfer Case Shudder or Binding
• Transfer Case Will Not Shift
• Transfer Case Jumps Out of Gear
• Symptoms - Transfer Case
• Transfer Case Disassemble
• Transfer Case Assemble
• Front Output Shaft Seal Replacement
• Input Shaft Seal Replacement
• Approximate Fluid Capacities
• Special Tools