Slip Condition In 2nd 3rd Or 4th - Damaged 2-4 Band Or 3-4 Clutch - keywords 4L60E 4L65E 4L70E automatic bind body busy chatter fourth second shift shudder third valve

This PI was superseded on 10/19/07 to remove engineering investigation. Please discard PIP3136K.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

The 4L60E/4L65E/4L70E automatic transmission may experience a condition of slipping, late or missed shifts in 2nd 3rd and 4th. An internal transmission disassembly may reveal a 2-4 band and or a 3-4 clutch being distressed.

Based on engineering transmission quality review sessions the following items should be inspected and or replaced as required. These items were found to be the cause of the distress to the 2-4 band and 3-4 clutch.

First check transmission fluid level. This transmission is very sensitive to low oil level.

Also check:

1. Low Line pressure (perform a PCS test as defined in SI)
2. 1-2 accumulator piston (56) cracked or broken
3. 2-4 Servo Piston Seals (18,19,21,26) for being cut or damaged
4. 2-4 Servo Apply Pin (13) for being nicked/scored /binding in the pin bore, damaged clutches will frequently cause the pin to have a rough finish where it passes through the case, this is a result of the clutch debris not usually the cause of the distressed clutches or band
5. 2-4 Servo Piston Bore for being scored or mismachined
6. 2-4 Band Anchor Pin (41) missing (low mileage)
7. Servo Feed Oil Passage blocked with sediment
8. Forward Clutch Apply Piston (630) Seals for being cut or damaged
9. Forward Clutch Apply Piston (630) for being cracked
10. Turbine shaft oil seal rings (619) for cut or damaged.
11. Turbine shaft check valve retainer and ball assembly (617) is in place in the end of the turbine shaft and has not come out and gone inside the torque converter, if the retainer or ball is missing from the turbine shaft the torque converter must be replaced
12. Turbine shaft apply fluid passage sealing balls are in place, these are pressed into the turbine shaft end inside the input housing
13. 3-4 Clutch Apply Piston (623) Seals for being cut or damaged
14. 3-4 Clutch Apply Piston (623) for being cracked
15. 3-4 Clutch and Forward Clutch oil feed passage blocked or restricted (should flow check the housing, and the passages should be inspected for proper location)
16. 3-4 Clutch check ball (620) for leaking
17. 3-4 Clutch air bleed orifice cup plug (698) is in place
18. Overrun Clutch Seal (632) damaged
19. #7 Checkball (located in the case) for not being seated or leaking
20. 4-3 Sequence Valve (383) undersized
21. Boost Valve (219) stuck causing low line pressure
22. Input Sun Gear to Input Carrier Thrust Bearing (700) damaged came apart
23. Selective Washer (616) extra washer installed
24. Oil Pump Body (200) cracked/damaged
25. Inspect the Forward Sprag for proper operation per eSI document #215197.

Also inspect to see if the rear stator shaft bushing (241) may be worn on one side or damaged. The turbine shaft (621) may also be damaged in the stator bushing journal area.

This condition may be caused by the stator shaft (214) being non-concentric with the pump cover (215). If this condition is encountered the pump cover should be replaced along with any residual damage.

If none of the above items are found to be the root cause for the failure the Input Housing, Forward Clutch Piston and 3-4 Clutch Piston should be replaced and resealed as well as resealing the 2-4 Servo.

If clutch debris is found, it is also very important to inspect the pressure control (PC) solenoid valve fluid screens. Clean or replace the PC solenoid as necessary. It is also important to flush and flow check the transmission oil cooler using J45096. Refer to SI "Automatic Transmission Oil Cooler Flushing and Flow Test" for the procedure.

Full sized trucks and utilities should have the shift cable properly adjusted and/or replaced if the cable is not holding proper adjustment.

In the event the transmission as a repeat 2-4 Band or 3-4 Clutch Failure the transmission may require replacement due to a possible transmission case concern.

BE SURE TO CONTACT THE PQC OR YOUR AVM FOR AUTHORIZATION IF A TRANSMISSION ASSEMBLY REPLACEMENT IS NECESSARY.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.