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

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 was released that improves 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).

** FIGURE 1**

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 CANSPO.

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.