For 1990-2009 cars

# MANUAL TRANSMISSION CLUTCH SLIPPAGE/CAUSE & CORRECTION

#### Models Affected: 1989-91 FIREBIRD, 1989-90 SUNBIRD, GRAND AM AND GRAND PRIX MODELS WITH MANUAL TRANSMISSION

This bulletin supersedes bulletin 89-7-34 issued 6/89. Please discard bulletin 89-7-34.

#### Note: For Firebird models in all model years, this applies to V-6 engines

FOR FIREBIRD MODELS ONLY

#### CONDITION:

Some owners of the above vehicles equipped with manual transmissions 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 the hydraulic linkage for any cracks, leaks, or loose mounting flange bolts. Check the fluid level in the 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.

Prior to removing the clutch housing to check clutch bolt torques, measure the clutch actuator pushrod travel. This measurement must be made with the actuator securely attached to the clutch housing. The travel should be 15-18mm while fully depressing the clutch pedal.

A. If the travel is less than 15mm, then the source of the clutch condition is located in the hydraulic linkage or pedal linkage. Inspect the hydraulic linkage for any cracks, leaks or loose mounting flange bolts. Check the fluid level in the clutch master cylinder reservoir. A low level may indicate a system leak or an under fill condition.

#### IMPORTANT: Check the pedal linkage for; the appropriate travel (minimum of 6.0"), any binding, or misalignment between the pedal assembly and clutch master cylinder.

B. If the fork travel is adequate, then the source of the clutch condition is located within the clutch housing and is most likely reduction of pressure plate bolt torque. If the bolts are not torqued properly, they should be removed and inspected for damage. After removing the bolts, inspect the clutch, flywheel and pilot bushing for any damage or excessive wear, and replace as required. When reinstalling the original or new clutch cover bolts (P/N 14004016), the torque should be 20 N.m (14.7 lbs. ft.) plus 30 degrees and a lock washer, (P/N 11500191) should be installed with each bolt. Reference section 7C of the 1989, 1990 or 1991 Service Manual for specific clutch installation, removal, and inspection instructions.

ALL OTHER VEHICLES

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 be the reduction of pressure plate bolt 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 lbs. ft.) plus 30 degrees and a lock washer (P/N 11500191) should be installed with each bolt. Thread locking compound should also be used. Reference Section 7C of the applicable Service Manual for specific clutch installation, removal, and inspection instructions.

Parts are currently available from G.M.S.P.O.

Use applicable labor operation and time.

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.