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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1984 🢒 GMC G Van 🢒 Bulletins 🢒 VIBRATION OR SHUDDER AT LAUNCH INSPECT PROPSHAFT AND U-JOINT

VIBRATION OR SHUDDER AT LAUNCH INSPECT PROPSHAFT AND U-JOINT

MODELS: 1983-84 G-2500 WITH AUTOMATIC TRANSMISSION

Some 1983-84 G-2500 vans may experience a vehicle vibration between 35-55 mph or a shudder at vehicle launch. This condition is generally isolated to vans with either the THM 400 or 700-R4 automatic transmission and equipped with a two-piece propshaft. If this condition is encountered, inspect (and repair if necessary) the propshaft and u-joint using the diagnosis chart in Section 4A of the Light Duty Service Manual. If the condition is still present after this inspection and the necessary repair, use the following procedure to determine if the prop-shaft is straight from the transmission to the rear axle.

1. Raise the vehicle on a hoist.

2. Stand behind the vehicle and sight down the propshaft from the center of the rear axle to the transmission.

3. If the propshaft is not straight (e.g., center bearing support is offset to one side), the center bearing support should be relocated (see Il- lustration No. 1).

4. To relocate the hanger, support the propshaft with a jack stand, remove the center bearing hanger bolts, and move the bearing hanger (side to side) to make the propshaft as straight as possible.

5. Drill two new holes in the hanger support frame member and reinstall the bolts and torque to 15-22 N.m. (20-30 ft. lbs.).

6. Lower the vehicle and road test.


Object Number: 84761 Size: FS

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.