BUZZ/LT.SHAKE IN SEAT OR DASH MUST REPLACE CAB BODY MOUNTS
VEHICLES AFFECTED: 1983-85 C 1, 2 With 5.0L And 5.7L Engines -----------------------------------------
Some 1983-85 C 1, 2 trucks may experience a vehicle vibration (a light shake or 'buzzing' in the seat or dash area) condition' between 60-90 KPH. This condition is usually more pronounced if the vehicle is not loaded.
Refer to Sections 3E and 4A of the Light Duty Service Manual for procedures on checking wheels, tires and propshafts. If these procedures do not correct the condition, the following parts may be installed.
1983 Models
Replace the cab body mounts with mounts for the 1984-85 ttucks.
Part Number Description Quantity Required ----------- ----------- -----------------
15597600 Upper Cushion 4 15597629 Lower Cushion 4 14027472 Retainer 4
See Figure No. 1.
All Models
Inspect engine mounts to see if the engine mount is grounding out. If the tab on the mount sticks out too far, it is possible for the mount that is bolted to the chassis to ground out inside the support that is bolted to the engine (See Figure No. 2). If this condition exists, remove the mount and; using a bench grinder, grind the tabs for clearance and reinstall the mount. Do not remove more than 1/16 inch from any tab.
Replace the rear transmission mount with P/N 14049476. This mount can be used on the THM 350, THM 700-R4, and all manual transmissions.
Mount P/N 14049477 can be used on THM 400 turbo tranamissions.
See Figure No. 3.
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.
