DRIVELINE CLUNK DURING GARAGE SHIFT OR HARD ACCELERATION

Model and Year: 1990 C TRUCKS WITH 4L60/3L80/5LM60/HM-117 FORT WAYNE PRODUCED TRANSMISSIONS

This bulletin covers service and parts information for vehicles which may exhibit a clunking noise during a garage shift or a driveline clunk during hard acceleration. Vehicles may be affected if they were built at the Fort Wayne Plant and are within the following VIN number ranges:

1GCDC14K2LZ100013 - 1GCDC14Z2LZ101290

This condition can be repaired by installing a reinforcement plate in the tailshaft crossover support Figure 1.

To install the reinforcement plate, remove the nut and washer from the underside of the transmission crossmember. Install reinforcement plate onto the bolt that passes through crossmember and replace the washer and nut. Torque the nut 54 N-m (40 lb-ft).

Part Name Part Number ---------- ----------- Reinforcement Plate 15567681

Parts are currently available from GMSPO.

This information is not contained in any Service Manual.

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.