IDLE SHAKE OR VIBRATION NEW TRANSMISSION MOUNT

VEHICLES AFFECTED: 1988 - 1991 S1 TRUCKS (NEW TRANSMISSION MOUNT)

Some 1988-91 S truck (two wheel drive) and 2-door utility models equipped with 4.3L engines and either automatic or manual transmissions, may experience and idle shake or vibration. This condition is most noticeable at engine speeds below 1500 RPM.

If this condition is encountered, and cannot be corrected using normal diagnostics, a newly released rear transmission mount is currently in use on 1988-90 C1, C2 and C3 pickups with 4.3L engines and 3-speed automatic transmissions (M40). When installing this mount, new service washers (one washer per bolt) are required for retaining mount to transmission. Also install a new nut on the stud when attaching mount to crossmember.

IMPORTANT: This mount is not for use on 1991 S/T 4-door utility or any 1988-91 T model pickup or utility.

PARTS INFORMATION:

PART NUMBER DESCRIPTION QUANTITY

15567796 Mount 1

15614758 Washer 2

11501033 Nut 1

Parts are currently available from CANSPO.

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.