KNOCKING NOISE-TORSION BAR DAMAGED OR BROKEN-NEW PART

SUBJECT: KNOCKING NOISE-TORSION BAR SUPPORT INSULATOR DAMAGED/BROKEN

MODELS: 1988-91 T1 TRUCKS

Some owners of 1988-1991 T trucks may comment about a knocking or rattling sound coming from the underside of their vehicle. This sound can occur if the torsion bar support insulator is damaged or breaks. To correct this condition, a new more durable torsion bar insulator has been released. The new insulator is visually identical to the previous insulator and the installation procedure has not changed (reference service manual X9129 section 3C).

VEHICLES INVOLVED:

The new torsion bar support insulators have been installed on vehicles after the following VIN breakpoints.

Shreveport GMC Truck 1GNCT18ZXM8258277 Chevrolet 1GDCT14Z9M8801063

Pontiac GMC Truck 1GTCS14Z6M0527312 West Chevrolet 1GCCS14A7MO190577

Moraine GMC Truck 1GKDT13Z7M2507954 Chevrolet 1GCCS19R1M2273070 Oldsmobile 1GHDT13Z8M2705805

SERVICE PARTS INFORMATION:

Part Number Description --------- ------------------------------ 15677665 Insulator, Torsion Bar Support

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

Labor Operation: E3340 Labor Time: 0.5 hr.

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.