A/T - No Reverse, Slips In Low/Reverse

9230buick02

Bulletin: 92-73T40-1

Date: June '92

Ref. No.: 92-238-73T40

Corp. Ref. No.: 277123


SUBJECT:
SLIPS IN LOW/REVERSE-NO REVERSE
(DIAGNOSE/REPLACE LOW/REVERSE CLUTCH)

MODELS AFFECTED:
1986-89 SKYHAWK
1986-92 SKYLARK
1986-92 CENTURY WITH 3T40 TRANSAXLE


CONDITION:

Some 1986-92 vehicles equipped with HYDRA-MATIC 3T40 transaxles may exhibit symptoms associated with wear in the low/reverse clutch pack. These symptoms are:

- Transaxle slips in manual low or reverse gears
- Transaxle inoperative in reverse gear





CAUSE:

If this condition exists (and upon inspection of the low/reverse components), it is noted that the piston outer lip seal is cut due to piston over-travel, this over-travel could possibly cause flattening of the low/reverse release spring (655) and deflection of the low/reverse clutch spring retainer (656).

CORRECTION:

Proper diagnostics for either of the above symptoms should be performed prior to attempted repair for any condition. Diagnosis should include:

- Check fluid levels
- T/V cable adjustment
- Fluid pressure check
- Manual valve secured
- Low/reverse pipe not bent; washer seal/O-ring secured; pipe brackets tight
- Low/reverse piston seals uncut and properly installed
- No loose retainers
- Cup plug seal properly installed (not cut)
- Backing plate in proper location
- Driven sprocket support Teflon seals
- Direct clutch seals


If the diagnostic conditions are met and further repair is required, both the below listed service parts should be replaced along with any low/reverse clutch components.

SERVICE PARTS INFORMATION:

Part Name/Service Package Package Number

Low/Reverse Clutch Release Spring (655) 8628222
Low/Reverse Clutch Retainer and Snap Ring 8664961
(656/657)

These service packages are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

Refer to the "Automatic Transaxle Diagnosis/Unit Repair" section of your service manual for necessary low/reverse clutch diagnostic and repair information.