REAR DRIVELINE SQUEAK REPLACE THRUST CAP BUMPER

VEHICLES AFFECTED: 1984-85 'T' Car ---------------

Some 1984-85 'T' Cars may exhibit a 'squeak' noise at low speeds coming from the rear of the vehicle.

This condition has been determined to be the result of improperly seated differential stem pinion gear thrust caps contacting the polyurethane bumper of the rear axle extension asaembly (see Illustration).

Vehicles exhibiting this condition can be yepaired by replacing the thrust cap polyurethane bumper and applying a powder graphite to the thrust cap face following procedures below:

1. Remove rear axle extension assembly from vehicle following applicable procedure in 1984-85 'T' Car Shop Manual.

2. Remove thrust cap from stem pinion gear and discard.

3. Inspect chamfer on end of stem pinion gear. Clean up as required utilizing a file to ensure chamfer is uniform and no burrs are present.

4. Position new thrust cap, P/N 8932649, on end of stem pinion gear. With concave end of tool J-29194, steering linkage installer, against thrust cap face, drive cap onto stem pinion gear.

NOTICE: A properly seated thrust cap will visually appear to run parallel to the stem pinion gear nut when rear wheel is rotated.

5. Secure rear axle extension assembly in vise. Drill 3.175 mm (1/8 in.) holes around the circumference of the polyurethane bumper to aid in bumper removal. Remove bumper and thrust plate utilizing suitable pick.

6. Clean all debris from splined bore of extension shaft.

7. Install removed thrust plate and new bumper, P/N 459797, into extension shaft ensuring that bumper surface with mould marks and numbers are facing inboard. With appropriate size socket and hammer, seat bumper in extension shaft counterbore.

8. Apply a light film of oil to thrust cap face. Dust cap face with a liberal amount of powder graphite such as Panef Quality Dry Craphite Lubricant or equivalent.

9. Install extension housing assembly following applicable procedure in 1984-85 'T' Car 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.