HARSH 1-2 SHIFTS -NEW VALVE BODY ASSY. 3L80/(THM 400)

MODELS: 1989-90 C,K,R,VP TRUCKS AND G-VANS W/3L80 5.7L V8 TBI

BULLETIN COVERS:

Some HYDRA-MATIC 3L80 (THM 400) 5.7L V8 TBI models may experience a harsh 1-2 shift. A new Valve Body Assembly and Rear Accumulator Spring were released which improve the 1-2 shift feel.

DATE OF PRODUCTION CHANGE: (See Figure Below)

Beginning December 21, 1989 (Julian Date 355) all LMA, LWA and SAA 1990 HYDRA-MATIC 3L80 (THM 400) transmission models were built with the new Valve Body Assembly (49) and Rear Accumulator Spring (78).

SERVICE PARTS INFORMATION:

Part Number Part Name

8675778 Spring - Rear Accumulator (78) 8676823 Valve Assembly - Control (49)

Important

BOTH PARTS MUST BE SERVICED TOGETHER.

Parts are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

Refer to the Unit Repair Section of the appropriate Service Manual for the proper replacement procedures.

WARRANTY INFORMATION:

For vehicles repaired under warranty use:

Labor Operation: T8165 Labor Time: 1.3 hrs.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.