ERRATIC SHIFT/ NO SHIFT SEALER IN GOVERNOR PASSAGES

M1984-87 6000 AND BONNEVILLE MODELS EQUIPPED WITH THM 440-T4 (ME9)

BULLETIN COVERS:

Erratic shifts or no upshift in a THM 440-T4 transaxle may be caused by particles of hardened Imprex (TM) material lodging in the governor pressure channel. (Imprex (TM) is an "impregnation plastic" used in the manufacturing of cases to help seal the case and minimize porosity.)

SERVICE ACTION: (Figures 2 and 3) --------------- 1. Remove governor assembly (5) from transaxle and clean with solvent.

2. Inspect governor for binding weights and/or mispositioned springs. To verify operation, turn governor upside down and pour solvent into the governor shaft. Check for leakage past the checkballs. If leakage is noted, replace the governor assembly.

3. Reinstall governor cover (9) without the governor assembly.

4. Start the engine and move the selector lever to Drive (D) position. Allow the engine to run for 15-20 seconds.

5. Move the selector lever to Park (P) and stop the engine.

6. Reinstall the governor assembly (5) into the transaxle and road test the vehicle to verify transaxle operation.

If erratic shifts or a no upshift condition continues:

7. Remove and clean governor oil pipe retainer (129), orificed cup pluq (127) governor feed and return pipes (125, 124) accumulator cover (121) and governor screen (126).

SERVICE MANUAL REFERENCE:

Refer to the THM 440-T4 (ME9) Automatic Transaxle On-Car Service Section in the appropriate Service Manual for governor service information.

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.