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

9228pontiac01

Bulletin Number: 92-7-18
Reference Number: 277123
Publish Date: 6/92


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


Models
Affected:
1986-92 6000, SUNBIRD, GRAND AM, FIERO, LEMANS, GRAND PRIX AND TRANS SPORT MODELS WITH 3T40


TRANSAXLE APPLICATIONS:
1986-92 HYDRA-MATIC 3T40 TRANSAXLE (RPO MD9)

TRANSAXLE MODELS:
All

CONDITION:

Some 6000, Sunbird, Grand Am, Fiero, LeMans Grand Prix and Trans Sport models equipped with HYDRA-MATIC 3T40 transaxles and manufactured the model years 1986 through 1992 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: (See Figure 1)

If this condition exists (and upon inspection of the low /reverse components), and it is noted that the piston outer lip seal is cut due to piston overtravel, this overtravel 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 with the low/reverse clutch components using Labor Code K7580. Include the replacement of the low/reverse release spring (655), clutch spring retainer (656), and piston snap ring (657) as part of total repair (see Figure 1).

SERVICE PARTS INFORMATION:


Service
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.

Use applicable Labor Time Guide for labor hours.

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.