Automatic Transmission - 4l60-e/4l65-e (Introduction, Service & Replacement) Chevrolet Chevy Express G2500

Transmission Fluid Temperature (TFT) Sensor Specifications

Transmission Fluid Temperature (TFT) Sensor Specifications

Fastener Tightening Specifications

Fastener Tightening Specifications (Diagnosis 4L60-E)

Transmission General Specifications

Transmission General Specifications (4L60-E)

Fluid Capacity Specifications

Fluid Capacity

Torque Converter End Play Specifications

Torque Converter End Play Check

Range Reference

Range Reference Table

Shift Solenoid Valve State and Gear Ratio

Shift Solenoid Valve State and Gear Ratio 4L60-E

Shift Speed

Shift Speed (G Van 4L60-E)

Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic

TFP Manual Valve Position Switch Logic

Transmission Range Switch Logic

Transmission Range Switch Logic

Line Pressure

Line Pressure (4L60-E)

Component Resistance

Component Resistance Table

Automatic Transmission Schematic Icons

Automatic Transmission Schematic Icons Icon Icon Definition NOTE: The OBD II symbol is used on the circuit diagrams in order to alert the technician that the circuit is essential for proper OBD II emission control circuit operation. Any circuit which fails and causes the malfunction indicator lamp (MIL) to turn ON, or causes emissions-related component damage, is identified as an OBD II circuit

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Automatic Transmission Inline 20-Way Connector End View

AT Inline 20-Way Connector End , Engine Side Connector Part Information 12160493 Engine Harness Side 20-Way F Micro-Pack 100 W Series (GY) Pin Wire Color Circuit No. Function A L-GN 1222 1-2 Shift Solenoid Valve Control B YE/BK 1223 2-3 Shift Solenoid Valve Control C OG/BK 1228 Pressure Control (PC) Solenoid Valve High Control - Late Production C RD/BK 1228 Pressure Control (PC) Solenoid Valve High Control - Early Production D L-BU/WH 1229 PC Solenoid Valve Low Control E PK 1020 Ignition 0 Voltage F-K - - Not Used L YE/BK 1227 Transmission Fluid Temperature (TFT) Sensor Signal M TN 2762 Low Reference - Late Production M BK 2762 Low Reference - Early Production N PK 1224 TFP Switch Signal A P OG 1226 TFP Switch Signal C - Late Production P RD 1226 TFP Switch Signal C - Early Production R D-BU 1225 TFP Switch Signal B S WH 687 3-2 Shift Solenoid Valve Control T TN/BK 422 Torque Converter Clutch Solenoid Valve Control U BN 418 Torque Converter Clutch Pulse Width Modulation Solenoid Valve Control V-W - - Not Used

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AT Inline 20-Way Connector End , Transmission Side Connector Part Information 12160782 Transmission Harness Side 20-Way M Micro-Pack 100 W Series (GY) Pin Wire Color Circuit No. Function A L-GN 1222 1-2 Shift Solenoid Valve Control B YE 1223 2-3 Shift Solenoid Valve Control C PU 1228 Pressure Control (PC) Solenoid Valve High Control D L-BU 1229 PC Solenoid Valve Low Control E RD 839 Ignition 1 Voltage F-K - - Not Used L BN 1227 Transmission Fluid Temperature (TFT) Sensor Signal M GY 452 Low Reference N PK 1224 TFP Switch Signal A P OG 1226 TFP Switch Signal C R D-BU 1225 TFP Switch Signal B S WH 687 3-2 Shift Solenoid Valve Control T BK 422 Torque Converter Clutch Solenoid Valve Control U TN 418 Torque Converter Clutch Pulse Width Modulation Solenoid Valve Control V-W - - Not Used

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Automatic Transmission Internal Connector End Views

Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch Connector End , Wiring Harness Side Connector Part Information 12162213 Conn 5-Way F M/P 150.2 P2S (NA) Pin Wire Color Circuit No. Function A BN 1227 Transmission Fluid Temperature (TFT) Sensor Signal B GY 452 Low Reference C PK 1224 TFP Switch Signal A D OG 1226 TFP Switch Signal C E D-BU 1225 TFP Switch Signal B

1-2 Shift Solenoid (SS) Valve Connector End , Wiring Harness Side Connector Part Information 12162201 Conn 2-Way F M/P 150.2 P2S (NA) Pin Wire Color Circuit No. Function A RD 839B Ignition 0 Voltage B L-GN 1222 1-2 Shift Solenoid Valve Control

2-3 Shift Solenoid (SS) Valve Connector End , Wiring Harness Side Connector Part Information 12162201 Conn 2-Way F M/P 150.2 P2S (NA) Pin Wire Color Circuit No. Function A RD 839A Ignition 0 Voltage B YE 1223 2-3 Shift Solenoid Valve Control

Torque Converter Clutch Pulse Width Modulated (TCC PWM) Solenoid Valve Connector End , Wiring Harness Side Connector Part Information 12162202 Conn 2-Way F M/P 150.2 P2S (BU) Pin Wire Color Circuit No. Function A RD 839E Ignition 0 Voltage B TN 418 Torque Converter Clutch Pulse Width Modulated Solenoid Valve Control

3-2 Shift Solenoid (SS) Valve Assembly Connector End , Wiring Harness Side Connector Part Information 12146094 Conn 2-Way F M/P 150.2 P2S (M GY) Pin Wire Color Circuit No. Function A RD 839C Ignition 0 Voltage B WH 687 3-2 Shift Solenoid Valve Control

Pressure Control (PC) Solenoid Valve Connector End , Wiring Harness Side Connector Part Information 12146800 Conn 2-Way F M/P 150.2 (L-GY) Delphi Pin Wire Color Circuit No. Function A PU 1228 Pressure Control (PC) Solenoid Valve High Control B L-BU 1229 PC Solenoid Valve Low Control

Torque Converter Clutch (TCC) Solenoid Valve Connector End , Wiring Harness Side Connector Part Information 10478128 CBL Solenoid Valve Pin Wire Color Circuit No. Function A RD 839D Ignition 0 Voltage B BK 422 Torque Converter Clutch Solenoid Valve Control

Automatic Transmission Related Connector End Views

Tow/Haul Switch Connector End Connector Part Information 12047785 4-Way Conn 4 F M/P 150 (BK) Pin Wire Color Circuit No. Function A BK 350 Ground B BN/WH 230 Instrument Panel Lamps Dimming Control C - - Not Used D L-BU 1788 Tow/Haul Switch Signal

Vehicle Speed Sensor (VSS) Assembly Connector End , Wiring Harness Side Connector Part Information 15359366 Asm Conn 2-Way F GT 150 (BK) Pin Wire Color Circuit No. Function A YE 400 VSS Signal B PU 401 VSS Ground

Park/Neutral Position (PNP) Switch Connector End , Wiring Harness Side Connector Part Information 15416722 BK ASM Conn 12-Way F GT Pin Wire Color Circuit No. Function 1 D-GN 1433 Clutch Start Switch Signal 2 Plug GN 15305171 Not Used 3 Plug GN 15305171 Not Used 4 YE 772 Transmission Range Switch Signal B 5 BK/WH 771 Transmission Range Switch Signal A - Early Production 5 TN/WH 771 Transmission Range Switch Signal A - Late Production 6 GY 773 Transmission Range Switch Signal C 7 BK 1250 Ground 8 WH 776 Transmission Range Switch Signal P 9 L-GN 275 P/N Position Switch Signal 10 L-GN 1324 Back-up Lamp Supply Voltage 11 PK 339 IGN 1 Voltage 12 PK 139 IGN 1 Voltage

Removal Procedure

1. Apply the parking brake.
2. Position the steering column shift lever to park.
3. Remove the knee bolster trim panel. Refer to «Knee Bolster Replacement - Left»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
4. Remove the knee bolster bracket. Refer to «Knee Bolster Bracket Replacement - Left»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
5. Remove the clip securing the shift cable to the steering column bracket.
6. Remove the shift cable from the steering column shift control.
7. Pull back the carpet and insulation to gain access to the shift cable pass-through grommet.
8. Remove the rubber grommet from the floor panel.
9. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
10. Remove the shift cable from the stud ball.
11. Remove the locking clip from the cable at the bracket.
12. Unclip the cable from the retainers at the fuel lines and body.
13. Lower the vehicle.
14. Remove the shift cable from the vehicle.

Installation Procedure

1. Install the shift cable to the vehicle.
2. Raise the vehicle.
3. Remove the black shipping tab from the transmission end of the shift cable and discard the tab.
4. Install the shift cable to the transmission bracket.
5. Install the cable clip.
6. Install the shift cable end to the transmission shift control lever by pushing the cable end onto the transmission shift control lever stud ball.
7. Lock the primary lock.
8. Lock the secondary lock.
9. Attach the shift cable to the fuel line and body clips.
10. Lower the vehicle.
11. Install the rubber grommet to the floor panel.
12. Install the shift cable to the steering column shift control.
13. Install the clip securing the shift cable to the steering column bracket.
14. Install the cable to the shift lever ball stud.
15. Adjust the shift cable. Refer to «Automatic Transmission Range Selector Cable Adjustment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__automatic-transmission-range-selector-cable-adjustment) .
16. Install the knee bolster bracket. Refer to «Knee Bolster Bracket Replacement - Left»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.
17. Install the knee bolster trim panel. Refer to «Knee Bolster Replacement - Left»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages and Console.

Automatic Transmission Range Selector Cable Adjustment

1. Position the transmission shift control lever into park.
2. Apply the park brake.
3. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the end of the range selector cable from the range selector lever ball stud.
5. Position the transmission range selector lever to park. Rotate the range select lever clockwise until it reaches the full mechanical stop position.
6. Slide the locking tab retainer to the side.
7. Release the locking tab.
8. Install the end of the range selector cable to the range selector lever ball stud.
9. Engage the locking tab without disturbing the cable. This sets the adjustment.
10. Slide the locking tab retainer over the locking tab.
11. Lower the vehicle.
12. Check the transmission for proper operation.
13. Release the parking brake.

Tools Required

J 41364-A Neutral Position Adjustment Tool. See Special Tools and Equipment .

1. Apply the parking brake.
2. Shift the transmission into neutral.
3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the nut securing the transmission control lever to the manual shaft.
5. Remove the transmission control lever from the manual shaft.
6. Disconnect the electrical connectors from the switch.
7. Remove the bolts securing the park/neutral position switch to the transmission.
8. Remove the park/neutral position switch from the manual shaft. If the park/neutral position switch did not slide off the manual shaft, file the outer edge of the manual shaft in order to remove any burrs.

1. Install the switch to the transmission manual shaft by aligning the switch hub flats with the manual shaft flats.
2. Slide the switch onto the transmission manual shaft until the switch mounting bracket contacts the mounting bosses on the transmission.
3. Install the switch to the transmission with two bolts finger tight.
4. Position the tool J 41364-A onto the park/neutral position switch. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . Ensure that the two slots on the switch where the manual shaft is inserted are lined up with the lower two tabs on the tool.
5. Rotate the tool until the upper locator pin on the tool is lined up with the slot on the top of the switch. Tighten: Tighten the bolts securing the switch to 25 N.m (18 lb ft).
6. Remove the J 41364-A from the switch. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . If installing a new switch, remove the positive assurance bracket at this time.
7. Connect the electrical connectors to the switch.
8. Install the transmission control lever to the manual shaft with the nut. Tighten: Tighten the control lever nut to 25 N.m (18 lb ft).
9. Lower the vehicle.
10. Check the switch for proper operation. The engine must start in the P (Park) or N (Neutral) positions only. If proper operation of the switch can not be obtained, replace the switch.

Park/Neutral Position Switch Adjustment

1. Place the transmission range selector in the N (Neutral) position.
2. With an assistant in the drivers seat, raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Loosen the park/neutral position switch mounting bolts.
4. With the vehicle in the N (Neutral) position, rotate the switch while the assistant attempts to start the engine.
5. Following a successful start, turn the engine off.
6. Tighten the bolts securing the switch to the transmission. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
7. Lower the vehicle.
8. Check the switch for proper operation. The engine must start in the P (Park) or N (Neutral) positions only.
9. Replace the park/neutral position switch if proper operation can not be achieved. Refer to «Park/Neutral Position Switch Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .

1. Remove the instrument panel trim plate bezel. Refer to «Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.
2. Disconnect the electrical connector from the tow/haul switch.
3. Push in clips (1) on both sides of the switch.
4. Push the switch rearward to remove the switch from the trim.

1. Install the switch into the trim plate bezel opening by pushing the switch in until the clip (1) snap into place.
2. Connect the electrical connector to the tow/haul switch.
3. Install the instrument panel trim plate bezel. Refer to «Trim Plate Bezel Replacement - Instrument Panel (I/P) Cluster»(/chevrolet/chevy-express-g2500/1996-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges-and-console) in Instrument Panel, Gages, and Console.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Place a drain pan under the transmission oil pan.
3. Remove the oil pan drain plug, if equipped.
4. If necessary, remove the bolts and position aside the range selector cable bracket for clearance while lowering the pan. It is not necessary to remove the cable from the lever or bracket.
5. Remove the oil pan bolts from the front and sides of the pan only.
6. Loosen the rear oil pan bolts approximately 4 turns.
7. Lightly tap the oil pan with a rubber mallet in order to loosen the pan to allow the fluid to drain.
8. Remove the remaining oil pan bolts.
9. Remove the oil pan and the gasket.
10. Grasp firmly while pulling down with a twisting motion in order to remove the filter.
11. Remove the filter seal. The filter seal may be stuck in the pump; if necessary, carefully use pliers or another suitable tool to remove the seal.
12. Discard the seal.
13. Inspect the fluid color.
14. Inspect the filter. Pry the metal crimping away from the top of the filter and pull apart. The filter may contain the following evidence for root cause diagnosis: Clutch material Bronze slivers indicating bushing wear Steel particles
15. Clean the transmission case and the oil pan gasket surfaces with solvent, and air dry. You must remove all traces of the old gasket material.

1. Coat the new filter seal with automatic transmission fluid.
2. Install the new filter seal into the transmission case. Tap the seal into place using a suitable size socket.
3. Install the new filter into the case.
4. Install the oil pan and a new gasket.
5. Install the oil pan bolts. Tighten: Tighten the oil pan to transmission case bolts alternately and evenly to 11 N.m (97 lb in).
6. If previously removed, install the range selector cable bracket and bolts. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
7. Apply a small amount of sealant GM P/N 12346004 to the threads of the oil pan drain plug, if equipped.
8. Install the oil pan drain plug, if equipped. Tighten: Tighten the oil pan drain plug to 18 N.m (13 lb ft).
9. Lower the vehicle.
10. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) and «Fluid Capacity Specifications»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__fluid-capacity-specifications) .
11. Check the COLD fluid level reading for initial fill only.
12. Inspect the oil pan gasket for leaks.

1. Remove the upper oil cooler line from the radiator.
2. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. If equipped with AWD, remove the engine protector shield. Refer to «Engine Protection Shield Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
4. Remove the lower cooler line from the radiator.
5. Pull the plastic cap back from the quick connect fitting and down along the cooler line about two inches.
6. Using a bent-tip screwdriver, pull on one of the open ends of the retaining ring in order to rotate the retaining ring around the quick connect fitting until the retaining ring is out of position and can be completely removed.
7. Remove the retaining ring from the quick connect fitting.
8. Discard the retaining ring.
9. Pull the cooler line straight out from the quick connect fitting.
10. Remove the retaining ring (E-clips) securing the cooler line to the quick connect in order to remove the remaining cooler lines from the remaining quick connect fittings.
11. Remove the cooler lines from the retaining clip at the oil pan.
12. Remove the cooler lines from the vehicle.

1. Install a new retaining ring (E-clip) into the quick connect fitting using the following procedure
2. Hook one of the open ends of the retaining ring in one of the slots in the quick connect fitting.
3. Rotate the retaining ring around the fitting until the retaining ring is positioned with all three ears through the three slots on the fitting.
4. Do not install the new retaining ring onto the fitting by pushing the retaining ring.
5. Ensure that the three retaining ring ears are seen from inside the fitting and that the retaining ring moves freely in the fitting slots.
6. Install the new retaining ring (E-clip) into the remaining quick connect fittings.
7. Install the cooler lines to the vehicle.
8. Install the cooler lines into the quick connect fittings.
9. Insert the cooler line end into the quick connect fitting until a click is either heard or felt.
10. Do not use the plastic cap on the cooler line in order to install the cooler line into the fitting.
11. Pull back sharply on the cooler line in order to ensure that the cooler line is fastened into the quick connect fitting.
12. Position (snap) the plastic cap onto the fitting. Do not manually depress the retaining ring when installing the plastic cap onto the quick connect fitting.
13. Ensure that the plastic cap is fully seated against the fitting.
14. Ensure that no gap is present between the cap and the fitting.
15. Ensure that the yellow identification band on the tube is hidden within the quick connect fitting. A hidden yellow identification band indicates proper joint seating.
16. Do not install the cooler line end into the fitting incorrectly.
17. If you cannot position the plastic cap against the fitting, remove the retaining ring from the quick connect fitting per Step 5 of the cooler line removal procedure. Check the retaining ring and the tube end in order to ensure neither is bent. Replace the cooler line or the retaining ring if necessary, and reinstall per step 2 of the cooler line installation procedure.
18. Install the cooler lines into the retaining clip at the oil pan.
19. Install the flair nut securing the lower oil cooler line to the radiator. Tighten: Tighten the flair nuts to 45 N.m (33 lb ft).
20. Lower the vehicle.
21. Install the flare nut securing the upper cooler line to the radiator. Tighten: Tighten the flair nut to 45 N.m (33 lb ft).
22. Start the engine.

1. Pull the plastic cap back from the quick connect fitting and down along the cooler line about 5 cm (2 in).
2. Using a bent-tip screwdriver, pull on one of the open ends of the retaining ring in order to rotate the retaining ring around the quick connect fitting until the retaining ring is out of position and can be completely removed.
3. Remove the retaining ring from the quick connect fitting.
4. Discard the retaining ring.
5. Pull the cooler line straight out from the quick connect fitting.

1. Install a new retaining ring into the quick connect fitting using the following procedure
2. Hook one of the open ends of the retaining ring in one of the slots in the quick connect fitting.
3. Rotate the retaining ring around the fitting until the retaining ring is positioned with all three ears through the three slots on the fitting.
4. Do not install the new retaining ring onto the fitting by pushing the retaining ring.
5. Ensure that the three retaining ring ears are seen from inside the fitting and that the retaining ring moves freely in the fitting slots.
6. Install the cooler line into the quick connect fitting.
7. Insert the cooler line end into the quick connect fitting until a click is either heard or felt.
8. Do not use the plastic cap on the cooler line in order to install the cooler line into the fitting.
9. Pull back sharply on the cooler line in order to ensure that the cooler line is fastened into the quick connect fitting.
10. Position (snap) the plastic cap onto the fitting. Do not manually depress the retaining ring when installing the plastic cap onto the quick connect fitting.
11. Ensure that the plastic cap is fully seated against the fitting.
12. Ensure that no gap is present between the cap and the fitting.
13. Ensure that the yellow identification band on the tube is hidden within the quick connect fitting.
14. A hidden yellow identification band indicates proper joint seating.
15. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. Remove the grille assembly. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g2500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g2500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) .
2. Place a drain pan under the vehicle.
3. Disconnect the transmission oil cooler lines from the auxiliary oil cooler.
4. Remove the oil cooler lines from the auxiliary oil cooler. Refer to «Transmission Fluid Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
5. Remove the 4 bolts securing the auxiliary oil cooler to the radiator support.
6. Remove the auxiliary oil cooler.

1. Install the 4 bolts securing the oil cooler to the radiator support. Tighten: Tighten the bolts to 10 N.m (89 lb in).
2. Install the oil cooler lines to the auxiliary oil cooler. Refer to «Transmission Fluid Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . Tighten: Tighten the cooler lines to 23 N.m (17 lb ft).
3. Remove the drain pan.
4. Install the grille assembly. Refer to «Grille Replacement (Uplevel)»(/chevrolet/chevy-express-g2500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) or «Grille Replacement (Base)»(/chevrolet/chevy-express-g2500/1996-2012/remont/exteriorinterior-trim/#exterior-trim) .

J 29714-A Servo Cover Depressor. See Special Tools and Equipment .

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General information.
2. Remove the 2 heat shield retaining bolts and the heat shield from the transmission.
3. Remove the oil pan bolt below and to the left of the 2-4 servo cover.
4. Install the J 29714-A to the oil pan rail. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
5. Tighten the bolt on the J 29714-A in order to compress the servo cover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
6. Remove the servo cover retaining ring.
7. Loosen the bolt on the J 29714-A to release tension on the servo cover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
8. Remove the servo cover and O-ring seal. If the cover is hung up on the seal, use a pick (2) to pull and stretch the seal (1) out of the groove. Cut and remove the O-ring seal before removing the cover.
9. Remove the 2-4 servo assembly from the transmission.
10. Inspect the 4th apply piston, the 2-4 servo converter, 2nd apply piston, and the piston inner housing for the following defects: Cracks Scoring Burrs and nicks

1. Install the new seals on the pistons and the servo cover.
2. Lubricate the seals with clean transmission fluid.
3. Install the 2-4 servo assembly into the 2-4 servo bore.
4. Install the servo cover and O-ring seal.
5. Install the J 29714-A . See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
6. Tighten the bolt on the J 29714-A in order to compress the servo cover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
7. Install the servo cover retaining ring.
8. Remove the J 29714-A from the oil pan flange. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
9. Install the oil pan bolt. Tighten: Tighten the oil pan bolt to 11 N.m (97 lb in).
10. Install the 2 heat shield retaining bolts and the heat shield from the transmission. Tighten: Tighten the bolts to 17 N.m (13 lb f).
11. Lower the vehicle.
12. Fill the transmission to the proper level with approved fluid.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Compress the reverse boost valve sleeve into the bore of the oil pump to release tension on the reverse boost valve retaining ring.
4. Remove the reverse boost valve retaining ring, then slowly release tension on the reverse boost valve sleeve.
5. Remove the reverse boost valve sleeve (5) and the reverse boost valve (4).
6. Remove the pressure regulator isolator spring (3) and the pressure regulator valve spring (2).
7. Remove the pressure regulator valve (1).

1. Install the pressure regulator valve (1).
2. Install the pressure regulator isolator spring (3) and the pressure regulator valve spring (2).
3. Install the reverse boost valve (4) in the reverse boost valve sleeve (5).
4. Install the reverse boost valve (4) and sleeve (5) in the oil pump cover.
5. Compress the reverse boost valve sleeve into the bore of the oil pump to expose the retaining ring slot.
6. Install the reverse boost valve retaining ring, then slowly release tension on the reverse boost valve sleeve.
7. Install the transmission oil filter and pan. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
8. Lower the vehicle.
9. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. Remove the transmission fluid level indicator from the fluid fill tube.
2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
3. Remove the bolt securing the transmission fluid fill tube bracket to the engine.
4. Remove the nut securing the transmission fluid fill tube bracket to the transmission. Remove the upper transmission fill tube from the vehicle.
5. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
6. Remove the transmission pan drain plug. Drain the fluid into an approved container.
7. Remove any dirt from the transmission where the fluid fill tube enters the transmission case.
8. Remove the transmission fluid fill tube from the transmission. Pull the tube upward from the transmission.
9. Remove the transmission fill tube seal.
10. Clean the metal parts using solvent. Do not allow the solvent to enter the transmission.
11. Air dry the parts.

1. Install a new oil level indicator tube seal into the transmission case.
2. Install the oil level indicator tube into the seal.
3. Lower the vehicle.
4. Install the upper transmission fill tube to the vehicle and into the lower fill tube.
5. Install the nut securing the oil level indicator tube bracket to the transmission. Tighten: Tighten the nut to 6 N.m (53 lb in).
6. Install the bolt securing the oil level indicator tube bracket to the engine. Tighten: Tighten the bolt to 6 N.m (53 lb in).
7. Fill the transmission to the proper fluid level. Refer to «Fluid Capacity Specifications»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__fluid-capacity-specifications) and to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. J 43911 Selector Shaft Seal Remover. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
2. J 43909 Selector Shaft Seal Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the Park/Neutral Position (PNP) Switch. Refer to «Park/Neutral Position Switch Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Be sure that the jackscrew for J 43911 is backed off and will not interfere with installation of the removal tool. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . Slide the seal remover tool over the selector shaft (2) with the threaded end of the tool towards the seal.
4. Rotate the removal tool so that the threads on the end of the tool engage the steel shell (1) of the seal. Use a wrench to be sure that the removal tool is firmly attached to the seal shell.
5. Rotate the jackscrew in the clockwise direction to remove the seal from the bore. Discard the seal that was removed.

1. Carefully slide a new selector shaft seal (1) over the selector shaft (2) with the wide face of the steel case facing outward. Position the seal so that it is starting to enter the seal bore.
2. Obtain J 43909 and remove the inner sleeve so that the tool will slide over the selector shaft. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Slide the J 43909 into position so that the end of the tool contacts the seal being installed. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . Use a mallet to strike the J 43909 and drive the new seal into the seal bore until it is seated at the bottom of the bore. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
4. Install the PNP Switch. Refer to «Park/Neutral Position Switch Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
5. Lower the vehicle.
6. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. Ensure that removal of the valve body is necessary before proceeding. IMPORTANT: The following components can be serviced without removing the valve body from the transmission: The torque converter clutch solenoid (1) The pressure control solenoid (2) The internal wiring harness (3) The 2-3 shift solenoid (4) The 1-2 shift solenoid (5) The transmission fluid pressure manual valve position switch (6) The 3-2 shift solenoid (7) The torque converter clutch pulse width modulation (TCC PWM) solenoid (8)
2. Remove the fluid level indicator.
3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the oil pan, gasket, and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
5. Disconnect the internal wiring harness electrical connectors from the following components: The transmission fluid pressure manual valve position switch (1) The 1-2 shift solenoid (2) The 2-3 shift solenoid (3) The pressure control solenoid (4) The TCC PWM solenoid (5) The 3-2 shift solenoid (6)
6. Remove the fluid indicator stop bracket bolt (2).
7. Remove the fluid indicator bracket (1).
8. Remove the TCC PWM solenoid retainer (2) with a small screwdriver. Rotate the solenoid (1) in the bore, if necessary, until the flat part of the retainer (2) is visible.
9. Remove the TCC PWM solenoid (1) in order to access the TCC solenoid retaining bolts.
10. Remove the TCC solenoid retaining bolts.
11. Remove the TCC solenoid (with O-ring seal) and wiring harness from the control valve body.
12. Reposition the harness to the side of the transmission case.
13. Remove the control valve body bolts which retain the transmission fluid pressure switch to the control valve body.
14. Remove the transmission fluid pressure switch.
15. Inspect the transmission fluid pressure switch for damage or debris.
16. Remove the manual detent spring retaining bolt.
17. Remove the manual detent spring.
18. Inspect the manual detent spring for cracks or damage.
19. Remove the remaining control valve body bolts.
20. Carefully begin to lower the control valve body down from the transmission case while simultaneously disconnecting the manual valve link.

1. Install the checkballs (1-7) in the valve body.
2. Install the control valve body to the transmission case while simultaneously connecting the manual valve link to the manual valve.
3. Verify that the manual valve link (3) is installed properly to the inside detent lever (1) and the manual valve (2).
4. Install one bolt (M6 X 1.0 X 47.5) hand tight in the center (1) of the valve body to hold it in place.
5. Do not install the transmission fluid indicator stop bracket and bolt at this time. Install but do not tighten the control valve body bolts which retain only the valve body directly. Each numbered bolt location corresponds to a specific bolt size and length, as indicated by the following: M6 X 1.0 X 65.0 (1) M6 X 1.0 X 54.4 (2) M6 X 1.0 X 47.5 (3) M6 X 1.0 X 35.0 (4) M8 X 1.0 X 20.0 (5) M6 X 1.0 X 12.0 (6) M6 X 1.0 X 18.0 (7)
6. Install the manual detent spring.
7. Install but do not tighten the manual detent spring retaining bolt.
8. Install the transmission fluid pressure switch.
9. Install but do not tighten the control valve body bolts which retain the transmission fluid pressure switch to the control valve body.
10. Tighten the control valve body bolts in a spiral pattern starting from the center, as indicated by the arrows. Tighten: Tighten the control valve body bolts (in sequence) to 11 N.m (97 lb in).
11. Ensure that the manual detent spring is aligned properly with the detent lever. Tighten: Tighten the manual detent spring bolt to 11 N.m (97 lb in).
12. Install the TCC solenoid with a new O-ring seal to the valve body.
13. Install the TCC solenoid bolts. Tighten: Tighten the TCC solenoid retaining bolts to 11 N.m (97 lb in).
14. Install the internal wiring harness to the valve body. The internal wiring harness has a tab (1) on the edge of the conduit.
15. Place the tab between the valve body and the pressure switch in the location shown (2). Press the harness into position on the valve body bolt bosses (1, 3).
16. Install the TCC PWM solenoid (1) to the control valve body.
17. Install the TCC PWM solenoid retainer (2).
18. Install the transmission fluid indicator stop bracket (1) and bolt (2). Tighten: Tighten the transmission fluid indicator stop bracket bolt to 11 N.m (97 lb in).
19. Connect the internal wiring harness electrical connectors to the following components: The transmission fluid pressure manual valve position switch (1) The 1-2 shift solenoid (2) The 2-3 shift solenoid (3) The pressure control solenoid (4) The TCC PWM solenoid (5) The 3-2 shift solenoid (6)
20. Install the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
21. Lower the vehicle.
22. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. Remove the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
2. Remove the 1-2 accumulator if necessary. Refer to «Accumulator Assembly, Spacer Plate, and Gaskets»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__accumulator-assembly-spacer-plate-and-gaskets) .
3. Disconnect the internal wiring harness electrical connectors from the following components: Transmission fluid pressure switch (1) 1-2 shift control solenoid (2) 2-3 shift control solenoid (3) Pressure control solenoid (4) TCC PWM solenoid (5) 3-2 control solenoid (6)
4. Remove the pressure control solenoid retainer.
5. Remove the pressure control solenoid.
6. Remove the 1-2 and 2-3 shift solenoid retainers.
7. Remove the 1-2 and 2-3 shift solenoids.
8. Remove the 3-2 control solenoid retainer.
9. Remove the 3-2 control solenoid.

1. Install the 3-2 control solenoid.
2. Install the 3-2 control solenoid retainer.
3. Install the 1-2 and 2-3 shift solenoids.
4. Install the 1-2 and 2-3 shift solenoid retainers.
5. Install the pressure control solenoid. Ensure that the electrical tabs are facing outboard.
6. Install the pressure control solenoid retainer and retaining bolt. Tighten: Tighten the pressure control solenoid retaining bolt to 11 N.m (97 lb in).
7. Connect the internal wiring harness electrical connectors to the following components: Transmission fluid pressure switch (1) 1-2 shift control solenoid (2) 2-3 shift control solenoid (3) Pressure control solenoid (4) TCC PWM solenoid (5) 3-2 control solenoid (6)
8. Install the 1-2 accumulator. Refer to «Accumulator Assembly, Spacer Plate, and Gaskets»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__accumulator-assembly-spacer-plate-and-gaskets) .
9. Install the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
10. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

J 28458 Seal Protector Retainer Installer. See Special Tools and Equipment .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the transmission oil pan and the filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Disconnect the transmission harness 20-way connector from the transmission internal harness pass-through connector. Depress both tabs on the connector and pull straight up; do not pry the connector.
4. Remove the 1-2 accumulator assembly. Do not remove the spacer plate. Refer to «Accumulator Assembly, Spacer Plate, and Gaskets»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__accumulator-assembly-spacer-plate-and-gaskets) .
5. Disconnect the internal wiring harness electrical connectors from the following components: Transmission fluid pressure switch (1) 1-2 shift control solenoid (2) 2-3 shift control solenoid (3) Pressure control solenoid (4) TCC PWM solenoid (5) 3-2 control solenoid (6)
6. Remove the TCC PWM solenoid retainer.
7. Remove the TCC PWM solenoid in order to access one of the TCC solenoid retaining bolts.
8. Remove the pressure control solenoid retainer.
9. Remove the pressure control solenoid.
10. Remove the TCC solenoid retaining bolts and the valve body bolts which retain the internal wiring harness.
11. Using J 28458 , release the pass-through electrical connector from the transmission case. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . Use the small end of the J 28458 over the top of the connector. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . Twist in order to release the four tabs retaining the connector. Pull the harness connector down through the transmission case.
12. Remove the TCC solenoid (with O-ring seal) and wiring harness assembly from the transmission case.
13. Inspect the TCC solenoid and wiring harness assembly for the following defects: Damage Cracked connectors Exposed wires Loose pins

1. Install the wiring harness and TCC solenoid assembly with a new O-ring seal to the transmission.
2. Install the pass-through electrical connector to the transmission case.
3. Install the valve body bolts which retain the internal wiring harness and install the TCC solenoid retaining bolts. Tighten: Tighten the control valve body retaining bolts to 11 N.m (97 lb in). Tighten the TCC solenoid retaining bolts to 11 N.m (97 lb in).
4. Install the pressure control solenoid. Ensure that the electrical tabs are facing outboard.
5. Install the pressure control solenoid retainer and retaining bolt. Tighten: Tighten the pressure control solenoid retaining bolt to 11 N.m (97 lb in).
6. Install the TCC PWM solenoid to the control valve body.
7. Install the TCC PWM solenoid retainer.
8. Connect the internal wiring harness electrical connectors to the following components: Transmission fluid pressure switch (1) 1-2 shift control solenoid (2) 2-3 shift control solenoid (3) Pressure control solenoid (4) TCC PWM solenoid (5) 3-2 control solenoid (6)
9. Install the 1-2 accumulator. Refer to «Accumulator Assembly, Spacer Plate, and Gaskets»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement__accumulator-assembly-spacer-plate-and-gaskets) .
10. Connect the transmission harness 20-way connector to the transmission pass-through connector. Align the arrows on each half of the connector and insert straight down.
11. Install the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
12. Lower the vehicle.
13. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

Accumulator Assembly, Spacer Plate, and Gaskets

Tools Required

1. J 25025-B Pump and Valve Body Alignment Pin Set. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
2. J 36850 Transjel Lubricant. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Remove the control valve body. Refer to «Valve Body and Pressure Switch Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
4. Remove the accumulator cover retaining bolts.
5. Remove the 1-2 accumulator cover assembly.
6. Disassemble the 1-2 accumulator. Blow compressed air into the 1-2 accumulator cover, as shown, to remove the 1-2 accumulator piston. Remove the 1-2 accumulator inner and outer springs.
7. Inspect the 1-2 accumulator inner and outer springs for cracks.
8. Remove the 1-2 accumulator piston seal (1) from the 1-2 accumulator piston.
9. Inspect the 1-2 accumulator piston for the following defects: Porosity Cracks Scoring Nicks and scratches
10. Inspect the 1-2 accumulator cover for the following defects: Porosity Cracks Scoring Nicks and scratches
11. Remove the spacer plate support retaining bolts.
12. Remove the spacer plate support.
13. Remove the spacer plate to valve body gasket, the spacer plate and the spacer plate to transmission case gasket.
14. Remove the 3-4 accumulator piston (2).
15. Inspect the 3-4 accumulator spring for cracks.
16. Remove the 3-4 accumulator piston seal (1) from the 3-4 accumulator piston.
17. Inspect the 3-4 accumulator piston for the following defects: Porosity Cracks Scoring Nicks and scratches

1. Install a new 3-4 accumulator piston seal (1) to the 3-4 accumulator piston.
2. Install the 3-4 accumulator pin (1) into the transmission case and retain the pin with J 36850 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Install the 3-4 accumulator piston (2) onto the pin (1) in the transmission case. Ensure that the 3-4 accumulator piston legs face away from the transmission case.
4. Install the J 25025-B (2, 3) to the transmission case. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
5. Install the spacer plate to transmission case gasket and the spacer plate to valve body gasket to the spacer plate; use J 36850 in order to retain the gaskets to the spacer plate. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) . The case gasket is identified by a C. Be sure to place the case gasket on the transmission case side of the spacer plate. The valve body gasket is identified by a V. Be sure to place the valve body gasket on the valve body side of the spacer plate.
6. Ensure that the solenoid screens (1, 2) are in place on the spacer plate.
7. Place the checkball (3) on the spacer plate in the location shown.
8. Place the 3-4 accumulator spring (4) on the spacer plate.
9. Install the spacer plate and related components to the transmission.
10. Install the spacer plate support and the spacer plate support retaining bolts. Tighten: Tighten the spacer plate support retaining bolts to 11 N.m (97 lb in).
11. After installing the spacer plate support (2), look through the hole in the spacer plate to ensure that the checkball (1) has remained in the proper location.
12. Install a new 1-2 accumulator piston seal (1) to the 1-2 accumulator piston.
13. Install the 1-2 accumulator inner and outer springs to the 1-2 accumulator cover.
14. Install the 1-2 accumulator piston onto the pin in the 1-2 accumulator cover. Ensure that the piston legs face the accumulator cover.
15. Install the 1-2 accumulator cover and the accumulator cover retaining bolts. Tighten: Tighten the accumulator cover retaining bolts to 11 N.m (97 lb in).
16. Remove the J 25025-B from the transmission case. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
17. Install the control valve body. Refer to «Valve Body and Pressure Switch Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
18. Install the transmission oil pan and filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
19. Lower the vehicle.
20. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

Transmission Extension Housing Rear Oil Seal Replacement

Tools Required

1. J 21426 Extension Housing Seal Installer. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
2. J 36850 Transjel Lubricant

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Place a drain pan under the vehicle.
3. Remove the propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) or «Propeller Shaft Replacement - Two Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-two-piece) in Propeller Shaft.
4. Remove the case extension housing rear oil seal. Use a flat bladed tool and carefully pry the seal from the housing.
5. Inspect the case extension housing for damage. Replace the extension housing if necessary. Refer to «Transmission Extension Housing Assembly Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .

1. Lubricate the inside diameter of the new seal with J 36850 .
2. Use the J 21426 with a soft faced mallet to install the seal. See «Special Tools and Equipment»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
3. Install the seal to the extension housing.
4. Install the propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) or «Propeller Shaft Replacement - Two Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-two-piece) in Propeller Shaft.
5. Remove the drain pan and lower the vehicle.
6. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Support the transmission with a transmission jack.
3. Place a drain pan under the vehicle.
4. Remove the propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) or «Propeller Shaft Replacement - Two Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-two-piece) in Propeller Shaft.
5. Remove the transmission mount. Refer to «Transmission Mount Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
6. Remove the case extension bolts (1).
7. Remove the case extension (2).
8. Remove and discard the case extension O ring seal (3).

1. Install a new case extension O ring seal (3).
2. Install the case extension (2). NOTE: Refer to Fastener Notice in Cautions and Notices.
3. Install the case extension bolts (1). Tighten: Tighten the case extension bolts (1) to 45 N.m (33 lb ft).
4. Install the transmission mount. Refer to «Transmission Mount Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
5. Install the propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) or «Propeller Shaft Replacement - Two Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-two-piece) in Propeller Shaft.
6. Remove the drain pan and the transmission jack.
7. Lower the vehicle.
8. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__transmission-fluid-checking-procedure) .

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the electrical connector from the speed sensor.
3. Remove the bolt.
4. Remove the speed sensor and the O-ring seal.
5. Inspect the seal and the transmission case. Replace the seal, if necessary.

1. Install the speed sensor and the O-ring seal into the transmission.
2. Install the bolt. Tighten: Tighten the bolt to 11 N.m (97 lb in).
3. Install the electrical connector to the speed sensor.
4. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Support the transmission with a transmission jack.
3. Remove the transmission support. Refer to «Transmission Support Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
4. Remove the transmission mount mounting bolts, for RWD vehicles.
5. Remove the transmission mount mounting bolts, for 4WD vehicles.
6. Remove the transmission mount from the vehicle.

1. Install the transmission mount to the vehicle.
2. Install the transmission mount mounting bolts, for 4WD vehicles. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
3. Install the transmission mount mounting bolts, for RWD vehicles. Tighten: Tighten the bolts to 50 N.m (37 lb ft).
4. Install the transmission support. Refer to «Transmission Support Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
5. Remove the transmission jack.
6. Lower the vehicle.

1. Disconnect the battery negative cable assembly from the battery negative terminal.
2. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g2500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
3. Support the vehicle with safety stands.
4. Disconnect the range selector cable from the transmission bracket and from the range selector lever.
5. If equipped with all wheel drive (AWD), remove the transfer case. Refer to «Transfer Case Assembly Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/transfer-case/#transfer-case-bw-4473-np3) in Transfer Case - BW 4473-NP3.
6. Remove the rear propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) or «Propeller Shaft Replacement - Two Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-two-piece) in Propeller Shaft.
7. Support the transmission with a transmission jack.
8. Remove the transmission support. Refer to «Transmission Support Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
9. Remove the exhaust pipe from the exhaust manifolds and the muffler assembly from the exhaust pipe. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g2500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
10. Remove the starter motor. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g2500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g2500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
11. Remove the converter sight shield.
12. Mark the flywheel and the torque converter alignment.
13. Remove the bolts that attach the torque converter to the engine flywheel.
14. Remove the transmission vent hose and the wiring harness from the transmission.
15. Remove the transmission fluid fill tube and the fill tube seal from the transmission. Refer to «Filler Tube and Seal Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
16. Plug the fluid fill tube opening in the transmission.
17. Disconnect the transmission oil cooler pipes from the transmission. Refer to «Transmission Fluid Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
18. Plug the transmission oil cooler pipe connectors in the transmission case.
19. Disconnect the wiring harness connectors from the transmission vehicle speed sensor and the park/neutral position switch.
20. Remove all vehicle harness wires, harness clips, tubes, brackets, and lines that may interfere with the removal of the transmission from the vehicle.
21. Remove the studs and the bolts securing the transmission to the engine.
22. Pull the transmission straight back.
23. Remove the transmission from the vehicle.
24. Inspect all the components for wear and damage.
25. Inspect all the seals and the fittings for signs of wear.
26. Inspect the torque converter for stripped or broken weld nuts.
27. Inspect the transmission case for cracks.
28. Perform the automatic transmission oil cooler flushing and flow test. Refer to «Automatic Transmission Oil Cooler Flushing and Flow Test (J 45096)»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__automatic-transmission-oil-cooler-flushing-and) or «Automatic Transmission Oil Cooler Flushing and Flow Test (J 35944-A)»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__automatic-transmission-oil-cooler-flushing-and) .

1. Support the transmission with a transmission jack.
2. Raise the transmission into place.
3. Slide the transmission straight onto the locating pins while lining up the marks on the flywheel and the torque converter.
4. Install the bolts that secure the transmission to the engine. Tighten: Tighten the studs and the bolts to 47 N.m (34 lb ft).
5. Install the bolts securing the torque converter to the engine flywheel. Tighten: First tighten all the bolts finger tight in order to insure proper converter seating. Tighten the bolts to 63 N.m (46 lb ft).
6. If equipped with AWD, install the transfer case. Refer to «Transfer Case Assembly Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/transfer-case/#transfer-case-bw-4473-np3) in Transfer Case - BW 4473-NP3.
7. Install the wiring harness connectors to the vehicle speed sensor and the park neutral position switch.
8. Position and install all vehicle harness wires, harness clips, tubes, brackets, and lines that were removed or moved prior to the transmission removal.
9. Install the transmission fluid fill tube and the fill tube seal. Refer to «Filler Tube and Seal Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
10. Install the transmission vent hose and the wiring harness to the transmission.
11. Install the sight shield.
12. Install the starter motor. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g2500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g2500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
13. Install the exhaust pipe to the exhaust manifolds and the muffler assembly to the exhaust pipe. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g2500/1996-2012/remont/exhaust/#engine-exhaust-system) in Engine Exhaust.
14. Install the transmission support. Refer to «Transmission Support Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) in Frame and Underbody.
15. Remove the transmission jack and the engine support stands.
16. Install the rear propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints) or «Propeller Shaft Replacement - Two Piece»(/chevrolet/chevy-express-g2500/1996-2012/remont/driveshaft-universal-joints/#propeller-shaft-and-universal-joints__propeller-shaft-replacement-two-piece) in Propeller Shaft.
17. Install the transmission range select cable to the transmission range select lever and the bracket.
18. Install the transmission oil cooler pipes. Refer to «Transmission Fluid Cooler Hose/Pipe Replacement»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-introduction-service-replacement) .
19. Flush the transmission oil cooler and the pipes whenever you remove the transmission for overhaul, or replacement of the torque converter, the pump, or the transmission case. Refer to «Automatic Transmission Oil Cooler Flushing and Flow Test (J 45096)»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__automatic-transmission-oil-cooler-flushing-and) or «Automatic Transmission Oil Cooler Flushing and Flow Test (J 35944-A)»(/chevrolet/chevy-express-g2500/1996-2012/remont/automatic-trans/#automatic-transmission-4l60-e4l65-e-troubleshooting__automatic-transmission-oil-cooler-flushing-and) .
20. Remove the safety stands.
21. Lower the vehicle.
22. Fill the transmission to the proper level using approved fluid.
23. Connect the battery negative cable assembly to the battery negative terminal. Tighten: Tighten the terminal bolt to 15 N.m (11 lb ft).

How to Use This Section

This section provides the following information

1. General diagnosis information on transmissions
2. Procedures for diagnosing the Hydra-matic transmission

When you diagnose any condition of the Hydra-matic transmission, begin with A Diagnostic Starting Point. This procedure indicates the proper path of diagnosing the transmission by describing the basic checks. This procedure will then refer you to the locations of specific checks. After you have determined the cause of a condition, refer to Repair Instructions for repair procedures. If the faulty component is not serviceable without removing the transmission from the vehicle, refer to Unit Repair for repair information.

Basic Knowledge

Note. Do not, under any circumstances, attempt to diagnose a powertrain condition without basic knowledge of this powertrain. If you perform diagnostic procedures without this basic knowledge, you may incorrectly diagnose the condition or damage the powertrain components.

You must be familiar with some basic electronics in order to use this section of the service manual. You should also be able to use the following special tools

1. A digital multimeter (DMM)
2. A circuit tester
3. Jumper wires or leads
4. A line pressure gage set

Diagnosis

Note. If you probe a wire with a sharp instrument and do not properly seal the wire afterward, the wire corrodes and an open circuit results.

Diagnostic test probes are now available that allow you to probe individual wires without leaving the wire open to the environment. These probe devices are inexpensive and easy to install, and they permanently seal the wire from corrosion.

Scheme 204

Scheme 205

Scheme 206

Plant and Shift Build Chart

Transmission Component and System Description

The mechanical components of the 4L60-E are as follows

1. A torque converter with an electronically controlled capacity clutch (ECCC) This transmission is equipped with an ECCC. The pressure plate does not fully lock to the torque converter cover. Instead, the pressure plate maintains a small amount of slippage, about 20 RPM, in SECOND, THIRD, and FOURTH gears, depending on the vehicle application. ECCC was developed to reduce the possibility of noise, vibration, or chuggle caused by TCC apply. Typical apply speeds are 49-52 km/h (30-32 mph) in THIRD gear and 65-73 km/h (40-45 mph) in FOURTH gear. Full lockup is available at highway speeds on some applications.
2. Torque converter assembly
3. Servo assembly and 2-4 band assembly
4. Reverse input clutch and housing
5. Overrun clutch
6. Forward clutch
7. 3-4 clutch
8. Forward sprag clutch assembly
9. Lo and reverse roller clutch assembly
10. Lo and reverse clutch assembly
11. Two planetary gear sets: Input and Reaction
12. Oil pump assembly
13. Control valve body assembly

The electrical components of the 4L60-E are as follows

1. 1-2 and 2-3 shift solenoid valves
2. 3-2 shift solenoid valve assembly
3. Transmission pressure control (PC) solenoid
4. Torque converter clutch (TCC) solenoid valve
5. TCC pulse width modulation (PWM) solenoid valve
6. Automatic transmission fluid pressure (TFP) manual valve position switch
7. Automatic transmission fluid temperature (TFT) sensor
8. Vehicle speed sensor assembly

For more information, refer to Electronic Component Description .

Transmission Adaptive Functions

The 4L60-E transmission utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components. By adjusting the line pressure, the PCM can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" and is similar to the closed loop fuel control system used for the engine.

In order for the PCM to perform a "shift adapt," it must first identify if an upshift is acceptable to analyze. For example, upshifts that occur during cycling of the A/C compressor or under extreme throttle changes could cause the PCM to incorrectly adjust line pressure. When an upshift is initiated, a number of contingencies, such as throttle position, transmission temperature, and vehicle speed, are checked in order to determine if the actual shift time is valid to compare to a calibrated desired shift time. If all the contingencies are met during the entire shift, then the shift is considered valid and the adapt function may be utilized if necessary.

Once an adaptable shift is identified, the PCM compares the actual shift time to the desired shift time and calculates the difference between them. This difference is known as the shift error. The actual shift time is determined from the time that the PCM commands the shift to the start of the engine RPM drop initiated by the shift. If the actual shift time is longer than the calibrated desired shift time, a soft feel or slow engagement, then the PCM decreases current to the pressure control (PC) solenoid in order to increase line pressure for the next, same, upshift under identical conditions. If the actual shift time is shorter than the calibrated desired shift time, a firm engagement, then the PCM increases current to the PC solenoid in order to decrease line pressure for the next, same, upshift under identical conditions.

The purpose of the adapt function is to automatically compensate the shift quality for the various vehicle shift control systems. It is a continuous process that will help to maintain optimal shift quality throughout the life of the vehicle.

Clearing Transmission Adaptive Pressure (TAP)

Transmission adaptive pressure (TAP) information is displayed and may be reset using a scan tool.

The adapt function is a feature of the PCM that either adds or subtracts line pressure from a calibrated base line pressure in order to compensate for normal transmission wear. The TAP information is divided into 13 units, called cells. The cells are numbered 4 through 16. Each cell represents a given torque range. TAP cell 4 is the lowest adaptable torque range and TAP cell 16 is the highest adaptable torque range. It is normal for TAP cell values to display zero or negative numbers. This indicates that the PCM has adjusted line pressure at or below the calibrated base line pressure.

Updating TAP information is a learning function of the PCM designed to maintain acceptable shift times. It is not recommended that TAP information be reset unless one of the following repairs has been made

1. Transmission overhaul or replacement
2. Repair or replacement of an apply or release component, clutch, band, piston, servo
3. Repair or replacement of a component or assembly which directly affects line pressure

Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, the PCM will need to relearn TAP values. Transmission performance may be affected as new TAPs are learned. Learning can only take place when the PCM has determined that an acceptable shift has occurred. The PCM must also relearn TAP values if it is replaced.

Scheme 207

The 1-2 and 2-3 shift solenoid valves (also called A and B solenoids) are identical devices that control the movement of the 1-2 and 2-3 shift valves. The 3-4 shift valve is not directly controlled by a shift solenoid. The solenoids are normally-open exhaust valves that work in 4 combinations to shift the transmission into different gears.

The powertrain control module (PCM) energizes each solenoid by grounding the solenoid through an internal quad driver. This sends current through the coil winding in the solenoid and moves the internal plunger out of the exhaust position. When ON, the solenoid redirects fluid to move a shift valve.

The PCM-controlled shift solenoids eliminate the need for TV and governor pressures to control shift valve operation.

Scheme 208

The 3-2 shift solenoid valve assembly is a normally-closed, 3-port, ON/OFF device that is used in order to improve the 3-2 downshift. The solenoid regulates the release of the 3-4 clutch and the 2-4 band apply.

Scheme 209

The transmission pressure control solenoid is an electronic pressure regulator that controls pressure based on the current flow through its coil winding. The magnetic field produced by the coil moves the solenoid's internal valve which varies pressure to the pressure regulator valve.

The PCM controls the pressure control solenoid by commanding current between 0.1-1.1 amps. This changes the duty cycle of the solenoid, which can range between 5-95 percent, typically less than 60 percent. High amperage (1.1 amps) corresponds to minimum line pressure, and low amperage (0.1 amp) corresponds to maximum line pressure, if the solenoid loses power, the transmission defaults to maximum line pressure.

The PCM commands the line pressure values, using inputs such as engine speed and throttle position sensor voltage.

The pressure control solenoid takes the place of the throttle valve or the vacuum modulator that was used on past model transmissions.

Scheme 210

The torque converter clutch (TCC) solenoid valve is a normally-open exhaust valve that is used to control torque converter clutch apply and release. When grounded (energized) by the powertrain control module (PCM), the TCC solenoid valve stops converter signal oil from exhausting. This causes converter signal oil pressure to increase and move the TCC solenoid valve into the apply position.

Scheme 211

The torque converter clutch pulse width modulation solenoid valve controls the fluid acting on the converter clutch valve. The converter clutch valve controls the torque converter clutch (TCC) apply and release. This solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid valve provides a smooth engagement of the torque converter clutch by operating during a duty cycle percent of ON time.

Scheme 212

The transmission fluid pressure (TFP) manual valve position switch consists of five pressure switches (two normally-closed and three normally-open) on the control valve body that sense whether fluid pressure is present in five different valve body passages. The combination of switches that are open and closed is used by the PCM in order to determine the actual manual valve position. The TFP manual valve position switch, however, cannot distinguish between PARK and NEUTRAL because the monitored valve body pressures are identical in both cases.

The switches are wired to provide three signal lines that are monitored by the PCM. These signals are used to help control line pressure, torque converter clutch apply and shift solenoid valve operation. Voltage at each of the signal lines is either zero or twelve volts.

In order to monitor the TFP manual valve position switch operation, the PCM compares the actual voltage combination of the switches to a TFP combination table stored in its memory.

The TFP manual valve position switch signal voltage can be measured from each pin-to-ground and compared to the combination table. On the automatic transmission (AT) wiring harness assembly, pin N is signal A, pin R is signal B, and pin P is signal C. With the AT wiring harness assembly connected and the engine running, a voltage measurement of these three lines will indicate a high reading (near 12 volts) when a circuit is open, and a low reading (zero volts) when the circuit is switched to ground.

The transmission fluid temperature (TFT) sensor is part of the TFP manual valve position switch assembly.

Scheme 213

The vehicle speed sensor (VSS) assembly provides vehicle speed information to the PCM. The VSS assembly is a permanent magnet (PM) generator. The PM generator produces a pulsing AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. Output voltage varies with speed from a minimum of 0.5 volts at 100 RPM to more than 100 volts at 8,000 RPM. The PCM converts the pulsing voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and TCC scheduling.

Automatic Transmission Fluid Temperature Sensor

The automatic transmission fluid temperature (TFT) sensor is part of the automatic transmission fluid pressure (TFP) manual valve position switch. The TFT sensor is a resistor, or thermistor, which changes value based on temperature. The sensor has a negative-temperature coefficient. This means that as the temperature increases, the resistance decreases and as the temperature decreases, the resistance increases.

The PCM supplies a 5-volt reference signal to the TFT sensor and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the PCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. Refer to TFT Sensor Specifications for a complete comparison of sensor resistance, temperature and signal voltage.

The PCM uses the TFT sensor information to control shift quality and TCC application.

Scheme 214

The transmission range (TR) switch is part of the park/neutral position (PNP) and backup lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The powertrain control module (PCM) supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.

Scheme 215

Tow/Haul mode enables the operator to achieve enhanced shift performance when towing or hauling a load. When tow/haul mode is selected, the tow/haul switch input signal to the body control module (BCM) is momentarily toggled to zero volts. This signals the powertrain control module (PCM) to extend the length of time between upshifts and increase transmission line pressure. Cycling the tow/haul switch again disables tow/haul mode and returns the transmission to a normal shift pattern.

Scheme 216

The transmission electrical connector is an important part of the transmission operating system. Any interference with the electrical connection can cause the transmission to set diagnostic trouble codes or affect proper operation.

The following items can affect the electrical connection

1. Bent pins in the connector from rough handling during connection and disconnection
2. Wires backing away from the pins or coming uncrimped, in either the internal or the external wiring harness
3. Dirt contamination entering the connector when disconnected
4. Pins in the internal wiring connector backing out of the connector or pushed out of the connector during reconnection
5. Transmission fluid leaking into the connector, wicking up into the external wiring harness and degrading the wire insulation
6. Moisture intrusion in the connector
7. Low pin retention in the external connector from excessive connection and disconnection of the wiring connector assembly
8. Pin corrosion from contamination
9. Damaged connector assembly

Remember the following points

1. In order to remove the connector, squeeze the two tabs toward each other and pull straight up without pulling by the wires.
2. Limit twisting or wiggling the connector during removal. Bent pins can occur.
3. Do not pry the connector off with a screwdriver or other tool.
4. Visually inspect the seals to ensure that they are not damaged during handling.
5. In order to reinstall the external wiring connector, first orient the pins by lining up the arrows on each half of the connector. Push the connector straight down into the transmission without twisting or angling the mating parts.
6. The connector should click into place with a positive feel and/or noise.
7. Whenever the transmission external wiring connector is disconnected from the internal harness and the engine is operating, DTCs will set. Clear these DTCs after reconnecting the external connector.

Special Tools

Special Tools Illustration Tool Number/Description Scan Tool J 21366 Converter Holding Strap J 21426 Extension Housing Seal Installer J 21867 Pressure Gage J 25025-B Pump and Valve Body Alignment Pin Set J 28458 Seal Protector Retainer Installer J 29714-A Servo Cover Depressor J 35616-B GM Terminal Test Kit J 35944-A Transmission Oil Cooler Flusher J 35944-22 Transmission Oil Cooler Flushing Fluid J 35944-200 Cooler Flushing Adapter J 36850 Transjel Lubricant J 38417 Speed Sensor Remover/Installer J 39200 Digital Multimeter (DMM) J 41364-A Park/Neutral Switch Aligner J 43909 Selector Shaft Seal Installer J 43911 Selector Shaft Seal Remover J 44152 Jumper Harness (20 pins) J 44246 Solenoid Testing Kit J 45096 Transmission Oil Cooling System Flush and Flow Test Tool

Scheme 217

Scheme 218

Scheme 219

Scheme 220

Scheme 221

Scheme 222

Scheme 223

See also:
• Knee Bolster Replacement - Left
• Lifting and Jacking the Vehicle
• Transmission Fluid Checking Procedure
• Engine Protection Shield Replacement
• Fastener Notice
• Grille Replacement (Uplevel)
• Engine Cover Replacement
• Propeller Shaft Replacement - One Piece
• Propeller Shaft Replacement - Two Piece
• Transfer Case Assembly Replacement
• Catalytic Converter Replacement (4.3L)
• Starter Motor Replacement (4.8L, 5.3L, and 6.0L)
• Automatic Transmission Oil Cooler Flushing and Flow Test (J 45096)
• Transmission Fluid Temperature (TFT) Sensor Specifications
• Automatic Transmission Range Selector Cable Adjustment
• Special Tools and Equipment
• Fluid Capacity Specifications
• Accumulator Assembly, Spacer Plate, and Gaskets
• Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic