BOOM DURING LOW TEMP. DRIVESHAFT VIBRATION

Some 1980-82 Chevettes may exhibit a driveline vibration induced body boom at low ambient temperatures which may diminish after a few miles of vehicle operation.

This condition has been determined to be the result of the low temperature sensitivity of a particular sourced center support bearing cushion.

Suspect cushions can be identified by the code letters "AY" molded on the forward face of the cushion when viewed as installed in vehicle (Figure 1).

Usage of suspect sourced cushions has been terminated in production and service assemblies incorporating usage of suspect cushions have been purged from WDDGM.

Vehicles exhibiting this condition can be corrected by replacement of the rear axle extention housing center support bracket and cushion assembly, P/N 361756, following procedure outlined in the applicable model year shop 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.