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Transfer Case - Bw 4473-np3 Chevrolet Express H1500

Transfer Case 25 illustrations ~5549 words

Approximate Fluid Capacities

ApplicationSpecification
MetricEnglish
DEXRON®VI GM P/N 88861003 (Canadian P/N 88861004)2.5 liters2.6 quarts

Approximate Fluid Capacities

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Adapter Bolts to Transmission50 N.m37 lb ft
Adapter Studs31 N.m23 lb ft
Case Bolts21 N.m15 lb ft
Drain Plug25 N.m18 lb ft
Fill Plug25 N.m18 lb ft
Mounting Nuts to Transfer Case50 N.m37 lb ft
Vehicle Speed Sensors17 N.m13 lb ft
Vent6 N.m53 lb in

Fastener Tightening Specifications

Adhesives, Fluids, Lubricants, and Sealers

ApplicationType of MaterialGM Part Number
United StatesCanada
Drain PlugSealant1234600410953480
Fill PlugSealant1234600410953480
Rear Case Half to Front Case HalfSealant1234614189022195
Transfer Case FillDEXRON®VI8886103719264717
Vehicle Speed Sensor O-RingDEXRON®VI8886103719264717
VentSealant1234600410953480

Adhesives, Fluids, Lubricants, and Sealers

Scheme 1

Scheme 1: Case Components
Scheme 1: Case Components
CalloutComponent Name
1Adapter Stud
2Front Case Half
3Locating Pin
4Rear Output Shaft Bearing Outer Retaining Ring
5Rear Case Half
6Wiring Harness Bracket
7Vehicle Speed Sensor (VSS)
8VSS O-Ring
9Rear Output Shaft Bushing
10Rear Output Shaft Seal
11Oil Fill Plug
12Case Half Bolt
13Oil Drain Plug
14Locating Pin
15Front Output Shaft Seal
16Vent
17Input Shaft Seal

Scheme 2

Scheme 2: Internal Components
Scheme 2: Internal Components
CalloutComponent Name
1Planetary Carrier Front Thrust Washer
2Planetary Pinion Gear Thrust Washer
3Planetary Pinion Gear
4Planetary Pinion Gear Thrust Washer
5Planetary Pinion Gear Shaft
6Planetary Carrier Rear Thrust Washer
7Input Shaft Rear Support Bearing
8Rear Output Shaft
9Annulus Gear
10Annulus Gear Retaining Ring
11Rear Output Shaft Bearing
12Rear Output Shaft Bearing Retaining Ring
13Speed Reluctor Wheel
14Rear Output Shaft Shipping Seal
15Sun Gear Bushing
16Sun Gear
17Viscous Coupling
18Drive Sprocket
19Driven Sprocket
20Front Output Shaft
21Front Output Shaft Cup Plug
22Front Output Shaft Rear Bearing
23Drive Chain
24Front Output Shaft Front Bearing
25Sun Gear Bearing
26Oil Restrictor
27Input Shaft
28Input Shaft Bushing
29Oil Scoop

Strategy Based Diagnostics

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 the easily accessible or visible system components for obvious damage, or for conditions which could cause the symptom.
  2. Inspect the transfer case for the proper fluid. Refer to «Transfer Case Fluid Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .

Symptom List

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

  1. «Transfer Case Popping Noise»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-popping-noise)
  2. «Transfer Case Whine or Rumble Noise»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-whine-or-rumble-noise)
  3. «Transfer Case Growl or Grinding Noise»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-growl-or-grinding-noise)
  4. «Transfer Case Clunk During Acceleration and Deceleration»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-clunk-during-acceleration-and)
  5. «Transfer Case No Front Drive»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-no-front-drive)
  6. «Transfer Case Leak Diagnosis»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-leak-diagnosis)
  7. «Transfer Case Viscous Coupling Test»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-viscous-coupling-test)

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 rumble 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 from the transfer case. Review the Symptoms - Transfer Case and perform the necessary inspections.
Planetary carrierInspect the 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 . Inspect the planetary carrier for deformation. Refer to Transfer Case Cleaning and Inspection . Replace the planetary carrier assembly if faulty. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Annulus gearInspect the annulus gear for teeth damage or wear. Refer to Transfer Case Cleaning and Inspection . Replace the annulus gear if faulty. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Sun gearInspect the sun gear for the following conditions: Gear tooth failure Worn or galled thrust surfaces Refer to Transfer Case Cleaning and Inspection . Replace the sun gear if faulty. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Thrust washersInspect the thrust washers for seizure to the planetary carrier. Inspect the thrust washers for galling. Replace the thrust washers if faulty and the mating component if damaged. Refer to Transfer Case Disassemble , and Transfer Case Assemble .

Transfer Case Growl or Grinding Noise

Transfer Case Clunk During Acceleration and Deceleration

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. Refer to Transfer Case Fluid Replacement .
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, if required. Refer to One-Piece Propeller Shaft Replacement , or Two-Piece Propeller Shaft Replacement . Replace the rear output shaft, if required. 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 Repair or replace the following components if faulty. Replace the slip yoke, if required. Refer to One-Piece Propeller Shaft Replacement , or Two-Piece Propeller Shaft Replacement . Replace the rear case half if the rear bushing is worn. Refer to Transfer Case Assemble .
Worn or faulty planetary carrierInspect the planetary carrier for the following conditions: Worn annulus gear Worn or faulty pinion gears Loose pinion gears Planetary carrier to mainshaft splines for wear Refer to Transfer Case Cleaning and Inspection . Replace the planetary carrier assembly and annulus gear if faulty. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Worn or missing sun gear thrust washersInspect to ensure the thrust washers are installed. Inspect the thrust washers and mating surface for excessive wear. Replace the worn or missing thrust washers. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Worn or damaged sun gearInspect the sun gear external gear teeth for excessive wear. Replace the sun gear or rear output shaft 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 damage to the retaining ring groove in the rear case half Repair or replace the following components if found faulty. Refer to Transfer Case Disassemble , and Transfer Case Assemble . Properly install a new rear output shaft bearing outer retaining ring. Replace the rear case half if the retaining ring groove is excessively worn.

Transfer Case Clunk During Acceleration and Deceleration

Transfer Case No Front Drive

CauseCorrection
DEFINITION: The transfer case is not delivering engine torque to the front propeller shaft. Review the Symptoms - Transfer Case and perform the necessary inspections.
Viscous coupling faultyInspect the transfer case fluid for being black. If the fluid is black, it is most likely caused by a viscous coupling failure. Test for a faulty viscous coupling. Refer to Transfer Case Viscous Coupling Test . Disassemble the transfer case. Refer to Transfer Case Disassemble . Inspect the viscous coupling for leaking. Refer to Transfer Case Cleaning and Inspection . Replace the viscous coupling if it is faulty. Refer to Transfer Case Assemble .
Planetary carrier faultyDisassemble the transfer case. Refer to Transfer Case Disassemble . Inspect for faulty planetary carrier components. Refer to Transfer Case Cleaning and Inspection . Replace any faulty planetary carrier components. Refer to Transfer Case Assemble .

Transfer Case No Front Drive

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. See below for suggested diagnostic method(s).
Special Tools GE 28431-6 Fluorescent Oil Dye GE 28428-E High Intensity Black Light Kit For equivalent regional tools, refer to Special Tools . Fluorescent Dye Method Add GE 28431-6 fluorescent oil dye to the transmission or transfer case to determine the source of the leak. Operate the vehicle. Inspect for the presence of dye within the oil leak using the GE 28428-E high intensity black light kit. A presence or non-presence of dye within the oil leak will indicate which component is the source of the leak. Powder Method CAUTION: Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings. Thoroughly clean the suspected leak area using a rag. Apply an aerosol type leak tracing powder to the suspected leak area. NOTE: Do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis. Operate the vehicle for 15-20 minutes under city driving conditions until normal operating temperatures are reached. Shut OFF the engine. Inspect the suspected leak area. Trace the leak path through the powder in order to find the source of the leak.
Drain plug or fill plug leakInspect for the correct sealer and amount of sealer on the plugs. Correctly install the plugs. Refer to Transfer Case Fluid Replacement .
Vehicle speed sensor (VSS) leakingRemove the VSS and 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 One-Piece Propeller Shaft Replacement , and Two-Piece Propeller Shaft Replacement . Replace the rear case half if the rear bushing is 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 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 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 front output shaft seal. Refer to Front Output Shaft Seal Replacement .
Leaking at the ventTransfer case overfilled Inspect for the correct transfer case fluid level. Refer to Transfer Case Fluid Replacement . Inspect the transmission fluid level. Refer to Transmission Fluid Level and Condition Check . If the transmission fluid level is low, and the transfer case fluid level is too high, 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 vent if it is leaking at the case. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Front case half to rear case half seam leakDisassemble, and seal the case halves again. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
Transfer case to adapter leakInspect for the following conditions: Loose mounting fasteners Gasket or sealant faulty The transfer case input shaft seal leaking Repair or replace the following components if found faulty: 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 Repair or replace the loose fasteners. Refer to Adapter Replacement . Replace the transfer case adapter gasket. Refer to Adapter Replacement .
Case leakingInspect for a cracked case or case porosity. Replace the faulty case half. Refer to Transfer Case Disassemble , and Transfer Case Assemble .
CAUTION
Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings.
NOTE
Do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.

Transfer Case Leak Diagnosis

Transfer Case Viscous Coupling Test

Special Tools

J 45382 Transfer Case Tester

For equivalent regional tools, refer to Special Tools .

Scheme 3

Scheme 3: Transfer Case Viscous Coupling Test
Scheme 3: Transfer Case Viscous Coupling Test

Note. Do not operate the vehicle on a hoist to diagnose the driveline components. Operating the vehicle on a hoist can cause over-spinning of the planetary pinion gears. Testing the viscous coupling operation by removing a propeller shaft and driving the vehicle causes the viscous coupling to fail.

To determine if the viscous coupling is operating correctly, use the following test procedure. The test determines if the viscous coupling is faulty from a totally locked up failure, or if the viscous coupling fluid has leaked out from being severely humped.

  1. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
  2. Set the parking brakes for the rear wheels.
  3. Position the transmission in NEUTRAL.
  4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  5. Remove the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  6. Install the J 45382 transfer case tester into the transfer case front output shaft.
  7. Using a torque wrench at 11 N.m (100 lb in) on the J 45382 transfer case tester , turn the front output shaft 90 degrees.
  8. Note the length of time it takes to turn the front output shaft the 90 degrees. If the front output shaft turns slow, and takes at least 10 seconds, the viscous coupling is operating correctly. If the front output shaft will not turn, the viscous coupling or the planetary carrier assembly could be locked-up. If the front output shaft turns easily, and the 11 N.m (100 lb in) cannot be obtained, the viscous coupling is faulty.

Removal Procedure

Note. When performing the following service procedures, use only hand tools to remove and install the fill or drain plugs.

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the fill plug from the transfer case.
  3. Remove the drain plug from the transfer case.

Installation Procedure

  1. Apply pipe sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads on the drain plug (2).
  2. Install the drain plug in the transfer case and tighten the drain plug to 25 N.m (18 lb ft).
  3. Fill the transfer case to the bottom of the fill hole with the proper fluid. Refer to «Approximate Fluid Capacities»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__approximate-fluid-capacities) .
  4. Apply pipe sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads on the fill plug (1).
  5. Install the fill plug and tighten to 25 N.m (18 lb ft)
  6. Lower the vehicle.

Note. When performing the following service procedures, use only hand tools to remove and install the fill or drain plugs.

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the fill plug from the transfer case.
  3. Remove the drain plug from the transfer case.
  1. Apply pipe sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads on the drain plug (2).
  2. Install the drain plug in the transfer case and tighten the drain plug to 25 N.m (18 lb ft).
  3. Fill the transfer case to the bottom of the fill hole with the proper fluid. Refer to «Approximate Fluid Capacities»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__approximate-fluid-capacities) .
  4. Apply pipe sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads on the fill plug (1).
  5. Install the fill plug and tighten to 25 N.m (18 lb ft)
  6. Lower the vehicle.
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the fill plug (1).
  1. Install the fill plug (1).
  2. Lower the vehicle.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the electrical connector from the speed sensor.
  3. Remove the speed sensor and the O-ring from the transfer case.
  1. Install the new speed sensor into the transfer case with a new O-ring seal. Tighten the right rear speed sensor to 17 N.m (13 lb ft).
  2. Install the electrical connector to the speed sensor.
  3. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .

Front Output Shaft Seal Replacement

Special Tools

  1. J 8092 Universal Handle
  2. J 43484 Front Output Shaft Seal Installer

For equivalent regional tools, refer to Special Tools .

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the front propeller shaft from the vehicle. Refer to «Front Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Insert a flat-tipped tool in the inner race.
  4. Pry the inner race forward.
  5. Insert a small pry bar in the inner race.
  6. Pry the inner part of the seal from the outer seal body.
  7. Remove the inner part of the seal.
  8. Insert a flat-tipped tool or small pry bar in the space between the outer race of the seal and the transfer case.
  9. Pry the outer race out of the transfer case.
  10. Remove the outer part of the seal.
  1. Using the J 43484 installer (2) and the J 8092 handle (1), install the transfer case output seal.
  2. Install the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Check the transfer case fluid level. Refer to «Transfer Case Fluid Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  4. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .

Rear Output Shaft Seal Replacement

Special Tools

J 45756 Rear Output Shaft Seal Installer

For equivalent regional tools, refer to Special Tools .

  1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Remove the rear output shaft seal by prying it out with a flat tipped tool.
  1. Using J 45756 installer , install a new rear output shaft seal.
  2. Install the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  3. Check the fluid level. Add fluid, if necessary.
  4. Lower the vehicle.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the transmission support crossmember. Refer to «Transmission Support Crossmember Replacement»(/chevrolet/express-h1500/2013-2013/remont/frames-subframes-crossmembers/#frame-and-underbody) .
  3. Drain the transfer case. Refer to «Transfer Case Fluid Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  4. Remove the rear propeller shaft from the transfer case. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  5. Remove the front propeller shaft from the transfer case. Refer to «Front Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  6. Remove the vent hose from the transfer case.
  7. Disconnect the electrical connector from the speed sensor.
  8. Unclip the fuel lines from the fuel line bracket.
  9. Install a suitable transmission jack to the transfer case.
  10. Remove the nuts from the transfer case to the adapter.
  11. Remove the transfer case from the transfer case adapter.
  12. Rotate the transfer case so that the transfer case is perpendicular to the torsion bar mounting bracket.
  13. Lower the transfer case.
  14. Remove the gasket from the transfer case.
  15. Remove the transfer case from the transmission jack.
  1. Install the transfer case on a suitable transmission jack.
  2. Install a new transfer case adapter gasket.
  3. Rotate the transfer case so that the transfer case is parallel to the torsion bar mounting bracket.
  4. Raise the transfer case into position.
  5. Rotate the transfer case so that the transfer case is aligned with the adapter.
  6. Install the transfer case on the adapter.
  7. Install the mounting nuts for the transfer case and tighten to 50 N.m (37 lb ft).
  8. Install the transmission support crossmember. Refer to «Transmission Support Crossmember Replacement»(/chevrolet/express-h1500/2013-2013/remont/frames-subframes-crossmembers/#frame-and-underbody) .
  9. Remove the transmission jack.
  10. Install the electrical connector to the speed sensor.
  11. Install the vent hose to the vent tube.
  12. Install the fuel lines to the fuel line bracket.
  13. Install the front propeller shaft. Refer to «Front Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  14. Install the rear propeller shaft. Refer to «One-Piece Propeller Shaft Replacement»(/chevrolet/express-h1500/2013-2013/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) .
  15. Fill the transfer case with the proper transfer case fluid. Refer to «Transfer Case Fluid Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  16. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the transfer case from the vehicle. Refer to «Transfer Case Assembly Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  3. Remove the mounting bolts from the adapter to the transmission.
  4. Remove the adapter from the transmission.
  5. Remove the seal between the transfer case and the adapter.
  6. Remove the transfer case to the adapter gasket.
  1. Install the new seal on the adapter.
  2. Install the adapter to the transmission.
  3. Install the adapter mounting bolts to the transmission and tighten to 50 N.m (37 lb ft).
  4. Install the new gasket to the adapter.
  5. Install the transfer case to the adapter. Refer to «Transfer Case Assembly Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  6. Install the transmission support crossmember. Refer to «Transmission Support Crossmember Replacement»(/chevrolet/express-h1500/2013-2013/remont/frames-subframes-crossmembers/#frame-and-underbody) .
  7. Remove the transmission jack from the transmission.
  8. Check the fluid level of the transfer case. Refer to «Transfer Case Fluid Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  9. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .

Input Shaft Seal Replacement

Special Tools

  1. J 23907 Slide Hammer
  2. J 36825 Output Shaft Oil Seal Remover
  3. J 45758 Seal Installer
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .
  2. Remove the transfer case from the adapter. Refer to «Transfer Case Assembly Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  3. Using the J 36825 remover (2) and J 23907 hammer (1) remove the input shaft seal. Poke a hole in the seal using a very small punch. Thread the J 36825 remover (2) into the hole.
  1. Position the seal on the input shaft.
  2. Using the J 45758 installer , install the input shaft seal in the transfer case.
  3. Install the transfer case to the adapter. Refer to «Transfer Case Assembly Replacement»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  4. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-h1500/2013-2013/remont/hoistjack/#general-information) .

Transfer Case Disassemble

Special Tools

  1. J-2619-A Slide Hammer with Adapter
  2. J 3289-20 Holding Fixture
  3. J 22912-B Rear Pinion and Axle Bearing Remover
  4. J 26941 Bushing and Bearing Remover - 3-4 inch
  5. J 36825 Output Shaft Oil Seal Remover - 4WD Models Only
  6. J 45358 Case Spreader
  7. J 45380 Transfer Case Rear Bushing Remover and Installer
  8. J 45759 Assembly Fixture
  9. J 45849 Bearing Remover

For equivalent regional tools, refer to Special Tools .

  1. Mount the J 3289-20 holding fixture to a sturdy workbench.
  2. Attach the J 45759 assembly fixture on the transfer case using the adapter studs. All of the transfer case disassembly procedures can be performed with the case mounted to the J 45759 assembly fixture.
  3. Install the J 45759 assembly fixture (2) into J 3289-20 holding fixture (1) and secure with pivot pin.
  4. Remove the drain plug. Ensure all of the transfer case fluid is drained out of the transfer case.
  5. Remove the front input shaft seal by inserting a flat-tipped screwdriver behind the inner race of the seal.
  6. Pry the inner seal race forward.
  7. Using a small pry bar, move the inner seal race forward on the front input shaft.
  8. Remove the inner seal race from the front input shaft.
  9. Insert a flat-tipped screwdriver or a small pry bar between the lip of the outer lip of the front output shaft seal and the transfer case.
  10. Remove the remaining part of the front output shaft seal from the transfer case.
  11. Remove the vehicle speed sensor (VSS) with O-ring seal.
  12. Remove the rear output shaft seal by prying out with a flat-blade screwdriver.
  13. Using the J 45380 bushing remover/installer , remove the rear output shaft bushing.
  14. Remove the transfer case retaining bolts and the washers.
  15. Mark the location of the brackets.
  16. Using the J 45358 case spreader between the tabs on the case halves, shear the sealer holding the case halves together.
  17. Using pry bars at each side of the case, remove the case from the locating pins.
  18. Remove the rear case half from the front case half. The rear output shaft will come out with the rear case half.
  19. Remove the planetary carrier assembly thrust washer.
  20. Remove the planetary carrier assembly.
  21. Remove the sun gear thrust washer.
  22. Remove the front input shaft.
  23. If the cup plug in the front output shaft is leaking, remove the plug using a brass drift.
  24. Remove the chain with the driven sprocket.
  25. Remove the sun gear with the drive gear and viscous coupling. Lift up on the sun gear assembly while tapping down on the input shaft with a soft-face hammer.
  26. Using a hydraulic press and J 22912-B pinion/bearing remover , remove the bearing from the sun gear.
  27. Remove the drive gear from the sun gear.
  28. Remove the viscous coupling from the sun gear.
  29. Remove the input shaft from the front case.
  30. Using the J-2619-A slide hammer (1) and the J 36825 seal remover - 4WD (2), remove the input seal. Poke a hole in the seal using a very sharp punch. Thread the J 36825 seal remover - 4WD (2) into the hole.
  31. Remove the input shaft bushing from the front case using a hammer and brass drift.
  32. Using a brass drift, remove the front output shaft bearing from the front case half.
  33. If necessary, remove the vent from the front case half.
  34. Remove the rear output shaft from the rear case half. Spread the rear output shaft rear bearing outer retaining ring (1). Using a soft-face hammer, tap on the end of the rear output shaft.
  35. Remove the annulus gear retaining ring.
  36. Remove the rear output shaft from the annulus gear.
  37. Inspect the bearing in the rear output shaft. Refer to «Transfer Case Cleaning and Inspection»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3) .
  38. If the bearing is faulty, remove the bearing using the J 45849 bearing remover. Install the finger part of the J 45849 bearing remover in the bearing. Thread the driver part into the fingers. Remove the bearing from the fingers by squeezing the fingers together.
  39. Remove the retaining ring for the rear output shaft bearing and the speed reluctor wheel.
  40. Using a hydraulic press and the J 22912-B pinion/bearing remover , remove the speed reluctor wheel and the rear output shaft bearing. Do not use the speed reluctor wheel again.
  41. Remove the rear bearing for the front output shaft from the rear case, using the J 26941 bushing/bearing remover (1) and the J-2619-A slide hammer (2).

Front Case Half

  1. Clean the front case half in cleaning solvent and air dry.
  2. Remove the metal shavings from the case half bolt holes.
  3. Remove the sealer from the case sealing surfaces.
  4. Inspect the case for being broken or cracked.
  5. Inspect the front output shaft front bearing bore (5) for the following conditions: Spun bearing Cracks
  6. Replace the front case half if any of the above is found.
  7. Inspect the sealing surfaces (2) for damage.
  8. Repair small scratches or nicks with a soft stone.
  9. Inspect the front case to transmission case mounting surface for damage.
  10. Inspect the case threaded bolt holes (3) for damage.
  11. Repair any damaged threads.
  12. Inspect the transmission to transfer case studs (1) for damage.
  13. Replace any damaged studs. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .
  14. Inspect the location pins (4 and 7) for being loose or missing.
  15. Repair or replace any damaged location pins.
  16. Inspect the input shaft bushing (6) for the following conditions: Excessive wear Scoring
  17. Inspect the front output shaft front bearing for the following conditions: Roughness Brinelling Pitting
  18. Replace the bearings if any of the above conditions are found. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__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 (1) 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 (2) for the following conditions: Spun bearing Cracks
  10. Inspect the rear output shaft rear bearing bore (5) for the following conditions: Spun bearing Cracks
  11. Replace the case if the bearing has spun. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .
  12. Inspect the retaining ring (4) for the rear output shaft rear bearing for being bent or twisted.
  13. Replace a faulty retaining ring.
  14. Inspect the rear output shaft bushing (3) for scoring or wear.
  15. Replace the case if the rear output shaft bushing is faulty. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .

Rear Output Shaft

  1. Clean the rear output shaft with the input shaft rear support bearing and the rear output shaft bearing in cleaning solvent.
  2. Air dry and ensure all solvent is removed from the bearings.
  3. Inspect the speed reluctor wheel (1) for damage.
  4. Replace the speed reluctor wheel if faulty. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .
  5. Inspect the rear output shaft bearing (2) for the following conditions: Scoring Pitting Brinelling Excessive wear
  6. Replace the rear output shaft bearing (2) if it is faulty. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .
  7. Inspect the input shaft rear support bearing (3) for the following conditions: Scoring Pitting Brinelling Excessive wear
  8. Replace the input shaft rear support bearing (3) if any of the above conditions are found. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .
  9. Inspect the rear output shaft splines (4) for wear or damage.
  10. Inspect the rear output shaft bearing area for a spun bearing.
  11. Replace the rear output shaft if any of the above conditions are found.

Input Shaft

  1. Clean the input shaft in cleaning solvent.
  2. Clean the input shaft oil galleries (3) and air dry.
  3. Inspect the oil scoop (2) for damage.
  4. Replace the oil scoop if it is damaged.
  5. Inspect the journals on the input shaft for the following conditions: The input gear bushing journal (1) The sun gear bushing journal (6) The input gear rear support bearing journal (5) Scoring Pitting Brinelling Excessive wear
  6. Inspect the input shaft internal input splines (7) and the planetary carrier splines (4) for damage or excessive wear. Witness marks are normal.
  7. Replace the input shaft if any of the above conditions are found.

Front Output Shaft

  1. Clean the front output shaft in cleaning solvent and air dry.
  2. Inspect for spun bearings at the front output shaft bearing areas.
  3. Inspect the front output internal splines and driven gear splines for damage or excessive wear.
  4. Replace the front output shaft if it is damaged.
  5. Inspect the cup plug in the front output shaft for leaking.
  6. Replace the cup plug if it is leaking. Refer to «Transfer Case Disassemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-disassemble) , and «Transfer Case Assemble»(/chevrolet/express-h1500/2013-2013/remont/transfer-case/#transfer-case-bw-4473-np3__transfer-case-assemble) .

Planetary Carrier

  1. Clean the planetary carrier in cleaning solvent. Do not disassemble the planetary carrier.
  2. Air dry, and ensure all cleaning solvent is removed from the bushings in the pinion gears (3). Do not spin the pinion gears with compressed air.
  3. Inspect the pinion gears for excessive looseness because of wear at the bushings or the shafts.
  4. Inspect the pinion gears for chipped teeth.
  5. Inspect the pinion gears for debris embedded in the root of the teeth.
  6. Inspect the planetary assembly for cracks at the web (1) of the housing.
  7. Inspect the thrust washer surface (2) for scoring or excessive wear.
  8. Replace the planetary carrier if any of the above conditions are found.
  9. Inspect the planetary carrier thrust washers for excessive wear or scoring.
  10. Replace the thrust washers if they are faulty.

Viscous Coupling

  1. Inspect the viscous coupling for leaking at the ball (1) in the housing. A black liquid would be visible if it is leaking.
  2. Replace the viscous coupling if it is leaking.
  3. Inspect for excessive worn splines (2).
  4. Replace the viscous coupling if the splines are faulty.

Drive Chain and Sprockets

  1. Clean the drive chain (2), drive sprocket (3), and driven sprocket (1) in cleaning solvent and air dry.
  2. Inspect the drive chain (2) for the following conditions: Loose link pins Binding or stiff links Debris embedded in the links Worn teeth surfaces
  3. Replace the chain if any of the above conditions are found.
  4. Inspect the driven sprocket (1) and the drive sprocket (3) for the following conditions: Chipped teeth Excessive worn gear surfaces Slight wear marks are normal. Debris embedded in the root of the teeth
  5. Replace the sprockets if any of the above conditions are found. The chain and sprockets may be replaced separately.

Sun Gear

  1. Clean the sun gear in cleaning solvent and air dry.
  2. Inspect the teeth on sun gear (1) for the following conditions: Chipped teeth Excessive worn gear surfaces Slight wear marks are normal. Debris embedded in the root of the teeth
  3. Inspect the input shaft bushing (2) for excessive wear or scoring. The bushing is only serviced with the gear.
  4. Replace the sun gear if they are faulty.

Annulus Gear

  1. Clean the annulus gear in cleaning solvent and air dry.
  2. Inspect the annulus gear for the following conditions: Chipped teeth Damage or excessive wear Witness marks are normal. Debris embedded in the root of the teeth
  3. Replace the annulus gear if any of the above conditions are found.

Transfer Case Assemble

Special Tools

  1. J 3289-20 Holding Fixture
  2. J 5590 Bearing and Seal Driver
  3. J 8092 Universal Driver
  4. J 22828 Input and Countershaft Race Installer
  5. J 36373 Input Sun Gear Ball Bearing Installer
  6. J 36850 Transjel Lubricant
  7. J 42176 Universal Driver Handle - Non-Threaded
  8. J 43484 Front Output Shaft Seal Installer
  9. J 45380 Transfer Case Rear Bushing Remover and Installer
  10. J 45540 Tone Ring and Bearing Installer
  11. J 45756 Rear Output Shaft Seal Installer
  12. J 45758 Input Seal Installer
  13. J 45759 Assembly Fixture
  14. J 45848 Bearing Installer

For equivalent regional tools, refer to Special Tools .

  1. If removed, install the transfer case mounting studs and tighten the mounting studs to 10 N.m (89 lb in).
  2. Attach the J 45759 assembly fixture (2) to the front case half using the adapter studs. All of the assembly procedures can be performed with the case mounted to the J 45759 assembly fixture (2).
  3. Install the J 45759 assembly fixture (2) into the J 3289-20 holding fixture (1) and secure with pivot pin.
  4. If removed, apply pipe sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads on the vent.
  5. Install the vent and tighten to 6 N.m (53 lb in).
  6. Install the front output shaft rear bearing in the rear case half. Use a hammer and a brass drift only on the outer bearing race. Ensure the bearing is kept square to the bore while installing.
  7. Install the input shaft bushing in the front case half using the J 36373 bearing installer and a hammer.
  8. Install the front bearing for the front output shaft in the front case half. Use a hammer and a brass drift only on the outer bearing race. Ensure the bearing is kept square to the bore while installing.
  9. If removed, install the input shaft rear support bearing in the rear output shaft using J 42176 driver handle (1) and J 45848 bearing installer (2).
  10. Using the J 22828 race installer and a hydraulic press, install the rear output shaft bearing with the retaining ring groove towards the gear.
  11. Using the J 22828 race installer and a hydraulic press, install a NEW speed reluctor wheel.
  12. Install a NEW retaining ring for the rear output shaft bearing.
  13. Install the rear output shaft in the annulus gear.
  14. Install a NEW annulus gear retaining ring.
  15. Install the rear output shaft in the rear case. Spread the rear output shaft rear bearing outer retaining ring (1). Using a soft-face hammer, tap on the rear output shaft.
  16. Ensure the retaining ring (1) is installed in the groove of the rear output shaft bearing (2).
  17. Install the input shaft in the front case.
  18. Install the viscous coupling on the sun gear.
  19. Install the drive gear on the sun gear.
  20. Using a hammer with the J 45540 ring/bearing installer (2) and the J 5590 driver (1), install the bearing on the sun gear. Ensure the bearing is fully seated against the drive gear.
  21. Install the sun gear, with the drive gear and the viscous coupling, on the input gear.
  22. If it is a new shaft, or if the cup plug was removed, install the cup plug in the front output shaft using a suitable driver. Install the cup plug 1 mm (0.039 in) from flush with the end of the shaft.
  23. Install the drive chain on the drive sprocket. The blue link on the chain faces up. Align the chain, if using it again, with the alignment marks made during disassembly.
  24. Install the driven sprocket and the chain.
  25. Install the front output shaft in the driven sprocket and the bearing.
  26. Lubricate the sun gear thrust washer with J 36850 lubricant or equivalent.
  27. Install the sun gear thrust washer.
  28. Install the planetary carrier assembly.
  29. Lubricate the sun gear thrust washer with J 36850 lubricant or equivalent.
  30. Install the planetary carrier thrust washer.
  31. Install the locating pins in the front case, if necessary.
  32. Apply a 3.175 mm (1/8 in) bead of room temperature vulcanizing (RTV) sealant GM P/N 12345739 (Canadian P/N 10953541) or equivalent to the mating surfaces of the front case half.
  33. Lower the rear case half into place.
  34. Install the case bolts, washers, and brackets.
  35. Tighten the case bolts to 21 N.m (15 lb ft).
  36. Using the J 45380 bushing remover/installer , install the rear output shaft bushing, if removed or new.
  37. Using the J 45756 seal installer , install the rear output shaft seal.
  38. Install the vehicle speed sensor (VSS) with a NEW O-ring seal.
  39. Tighten the VSS to 17 N.m (13 lb ft).
  40. Apply pipe sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads on the drain plug and fill plug.
  41. Install the drain plug and tighten to 25 N.m (18 lb ft).
  42. Install the fill plug and tighten to 25 N.m (18 lb ft).
  43. Using the J 43484 seal installer (2) and the J 8092 driver (1), install the front output shaft seal.
  44. Using the J 45758 seal installer , install the front input shaft seal.
  45. Remove the transfer case from the J 45759 assembly fixture.

General Description

The Borg Warner (BW) model 4473 RPO NP3 transfer case is a 1-speed, full time AWD, transfer case. The BW 4473 provides 1 operating mode, 4HI full-time AWD. The transfer case has a planetary differential gear set, which provides a 35 percent/65 percent torque split, front/rear, full time. Both axles are constantly being driven for maximum traction, and the best balance of vehicle handling characteristics under all operating conditions is provided.

The BW 4473 case halves are high-pressure die-cast aluminium. The transfer case requires DEXRON®VI Automatic Transmission Fluid (ATF) GM P/N 88861003 (Canadian P/N 88861004), which is red in color.

Scheme 4

Scheme 4: General Description
Scheme 4: General Description

The power flows from the transmission to the transfer case input shaft (1). The input shaft (1) delivers the power to the planetary center differential (4), which splits the torque 35 percent through the differential pinion gears (8) to the front sun gear (7), through the sprocket drive (2), via the chain (10) to the front output shaft (9) and to the front propeller shaft. 65 percent of the torque is delivered to the rear output, which goes through the differential ring gear (6), which is connected to the rear output shaft (5), and to the rear propeller shaft.

The viscous coupling (3), torque biasing device, has a series of opposing discs which are attached to the front and rear output shafts. 1 set turns with the front axle and the 1 set turns with the rear axle. The viscous coupling has a sealed housing, which is filled with high viscosity silicone fluid. When there is a speed difference between front and rear axles, the inner and outer plates of the coupling turn relative to each other. The silicone fluid provides resistance to the speed difference, and torque is transferred to the axles to equalize the speed difference. The tuning of the coupling is such that binding is not felt in tight turns, on dry surfaces, while being high enough to bias torque quickly to the wheels that have traction in a vehicle slip event. If the speed difference between the axles is high, the viscous coupling can go into hump mode. This occurs when the heat generated by the high speed difference expands the viscous fluid in the coupling, which results in pressure between the plates, forcing them in to contact each other, similar to a clutch pack. In the hump mode, the coupling can bias torque 100 percent to 1 axle. To prevent damage to the viscous coupling, the following should be avoided in the vehicle

  1. Do not tow with only 2 wheels on the ground.
  2. Do not drive with 1 propeller shaft removed.
  3. Do not drive with a mini spare tire for any extended period of time.
  4. Do not operate the vehicle on a hoist to diagnose the driveline components.

Customers may have concern that the transfer case is not operating properly, because 1 set of tires spun for a brief period. It is normal for 1 set of tires to spin until the viscous coupling engages. Turning off the traction control switch, if equipped, enhances the function of the viscous coupling. The viscous coupling, as described above, engages by heat. Allowing 1 set of tires to spin or slip for a very brief period, generates heat in the viscous coupling. The engine speed should be kept at a constant speed during the brief spin of the tires. Feathering the engine speed, or hard acceleration, will not allow the viscous coupling to operate properly.

Scheme 5

Scheme 5: Power Flow - No Wheel Slip
Scheme 5: Power Flow - No Wheel Slip

During normal operation, 100 percent engine torque is delivered to the input shaft (1) from the transmission. The torque is split 65 percent to the rear output shaft (5), and 35 percent to the front output shaft (9), by the planetary differential (4). Because there is not a loss in traction, or slip in the front or rear wheels, the viscous coupling (3) is locked in place and there is no shear mode or hump mode involved.

Scheme 6

Scheme 6: Power Flow - Front Wheel Slip
Scheme 6: Power Flow - Front Wheel Slip

When traction is lost at the front wheels, the viscous coupling (3) works in conjunction with the planetary differential (4) to bias the torque more to the rear wheels. The rear torque goes higher than 65 percent, up to 100 percent torque to the rear output shaft (5). The torque at the front output shaft (9) is lowered from 35 percent, to as low as 0 percent torque.

Scheme 7

Scheme 7: Power Flow - Rear Wheel Slip
Scheme 7: Power Flow - Rear Wheel Slip

When traction is lost at the rear wheels, the torque is biased to the front wheels. The torque to the front output shaft (9) goes higher than 35 percent, up to 100 percent. The torque at the rear output shaft (5) is lowered from 65 percent, to as low as 0 percent torque.

Special Tools

Illustration Tool Number/Description J 3289-20 Holding Fixture J 5590 Pinion Bearing Race Installer - Rear J 8092 Driver Handle J 22828 Input and Countershaft Race Installer 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 36373 Input Sun Gear Ball Bearing Installer J 36825 Output Shaft Oil Seal Remover - 4WD Models Only J 36850 Transjel Lubricant J 42176 Universal Driver Handle - Non-Threaded J 43484 Front Output Shaft Seal Installer J 45358 Case Spreader J 45380 Transfer Case Rear Bushing Remover and Installer J 45382 Transfer Case Tester J 45540 Tone Ring and Bearing Installer J 45756 Rear Output Shaft Seal Installer J 45758 Input Seal Installer J 45759 Assembly Fixture J 45848 Bearing Installer J 45849 Bearing Remover

Scheme 8

Scheme 8: Special Tools
Scheme 8: Special Tools

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13
Scheme 13

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

See also:
• One-Piece Propeller Shaft Replacement
• Transmission Fluid Level and Condition Check
• Lifting and Jacking the Vehicle
• Fastener Caution
• Transfer Case Seal Removal Caution
• Transmission Support Crossmember Replacement
• Machined Surface Damage Caution
• Transfer Case Description and Operation
• Transfer Case Popping Noise
• Transfer Case Whine or Rumble Noise
• Transfer Case Growl or Grinding Noise
• Transfer Case Clunk During Acceleration and Deceleration
• Transfer Case No Front Drive
• Transfer Case Leak Diagnosis
• Transfer Case Viscous Coupling Test
• Transfer Case Disassemble
• Transfer Case Assemble
• Special Tools
• Rear Output Shaft Seal Replacement
• Front Output Shaft Seal Replacement
• Input Shaft Seal Replacement
• Approximate Fluid Capacities