GM Service Manual Online
For 1990-2009 cars only

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

Model and Year: 1989-90 C, K, R, V, P TRUCK AND G VAN WITH 3L80 (THM 400) AUTOMATIC TRANSMISSION AND 5.7L ENGINE

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 that improve the 1-2 shift feel.

DATE OF PRODUCTION CHANGE: (Figure 1)

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.

SERVICE MANUAL REFERENCE:

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

Parts are currently available from GMSPO.


Object Number: 85960  Size: SF

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.