ENGINE VIBRATION OR MOAN NOISE (REPAIR PROCEDURE)

Model and Year: 1985-88 G VAN WITH 4.3L ENGINE

Some 1985-88 G Vans equipped with the 4.3L engine and automatic or manual transmissions may experience vehicle vibration under different driving conditions. Vehicles equipped with 3 speed automatic or manual transmissions and lower gear ratios (3.42/3.73 etc.) may experience a vibration, "drone" condition, at highway speeds while vehicles with 4 speed overdrive transmissions and higher gear ratios (3.08/3.23) may experience vehicle shudder and low speed vibration conditions.

If a 1985-88 G Van experiences a vehicle vibration condition that cannot be repaired using normal diagnostic procedures, a new engine mount P/N 17989409 (2 required) has been released to address this condition.

Use engine mount replacement procedures in section 6A4 of the appropriate 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.