MANUAL TRANSMISSION CLUTCH SLIPPAGE/CAUSE & CORRECTION

SUBJECT: MANUAL TRANSMISSION CLUTCH-SLIPPAGE (DIAGNOSIS)

VEHICLES AFFECTED: 1989-90 F, J, L, N AND W W/MANUAL TRANSMISSION

For F-cars in all model years, this applies to V-6 engines only.

FOR F-CARS ONLY

This bulletin should be used for 1989-1990 model year F-cars in conjunction with service bulletin number #91-7-100.

FOR F, J, L, N, AND W CARS

CONDITION:

---------- Some owners of the above vehicles equipped with manual transmission may comment about difficult shift effort or gear clash in all gears with the clutch pedal fully depressed.

CAUSE:

------ This reduced clutch disengagement may be the result of the clutch pressure plate cover to flywheel bolts working loose.

CORRECTION:

----------- In order to assist diagnosis and repair, it is suggested that the following diagnostic procedures be used:

A. Prior to removing the pressure plate, check for obvious hydraulic system leaks. Inspect hydraulic linkage for any cracks, leaks, or loose mounting flange bolts. Check fluid level in master cylinder reservoir. A low level may indicate a system leak or an under filled condition.

IMPORTANT: Slight dampness under the clutch master cylinder boot, slave cylinder, or tube fitting does not necessarily indicate a leaking condition, as there is a silicon lubricant present on the hydraulic clutch assembly.

If the hydraulic system does not show signs of leakage and the fluid level is correct, then the source of the clutch condition is located within the clutch housing and is most likely to be the reduction of pressure plate boot torque.

B. Access the pressure plate bolts and check for looseness. if the bolts are not torqued properly, they should be removed ONE AT A TIME, inspected for damage, and reinstalled. When reinstalling the original or new clutch cover bolts (P/N 14004016), the torque should be 20 N.m (14.7 ft.lbs.) plus 30 degrees and a lock washer (P/N #9439511) should be installed with each bolt. Reference Section 7C of the applicable Service Manual for specific clutch installation, removal, and inspection instructions.

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.