GEAR RATTLE/KNOCK 2ND GEAR INSTALL TORSION SPRING

MODELS: 1982-83 S/T TRUCKS EQUIPPED WITH BORG WARNER 4-SPEED MANUAL TRANSMISSIONS (RPO M77)

Some 1982-83 S/T trucks equipped with Borg Warner 4-speed manual transmissions may exhibit a "knock" or "rattle" noise while in 2nd gear and accelerating. This condition may be caused by the transmission's reverse idler teeth contacting the main shaft reverse gear teeth.

Vehicles with this condition can be corrected by adding a torsion spring, P/N 14079331, to the transmission's reverse relay lever following the recommended procedure:

1. Following instructions outlined in GMC Service Manual X-8229, Section 7B 1, or X-8329 S/T Truck 77mm. (4 spd.) Manual Transmission, remove, drain, and disassemble transmission to extent of removing clip that retains reverse relay lever to reverse lever pivot pin.

2. Holding reverse relay lever in position, unscrew pivot pin and remove from case.

3. Install torsion spring, P/N 14079331, between case and lever in orientation shown in Figure No. 1 with spring's long tang positioned in front of web of case.

Important: The view shown in figure No. 1 has various components (including reverse relay lever) removed to better illustrate how the spring is to be mounted and located in unit.

4. Apply non-hardening sealer to threads of pivot pin and install pin through case, torsion spring, and reverse relay lever and torque to 35-50 ft. lbs.

5. Install clip that retains reverse relay lever (and spring) to pivot pin as shown in Figure No. 2.

6. Using a suitable tool or hook fashioned similar to tne one shown in Figure No. 3, pull bent tang of torsion spring behind lever and hook end of spring over lever as shown.

7. Following instructions outlined in GMC Service Manuals X-8229 or X-8329, reassemble, fill with lubricant, and install transmission. If necessary, adjust clutch as required.

The torsion spring was effective in production transmissions at Borg Warner with the following model and serial numbers:

Model Serial No.

13-51-000-005 10463 13-53-000-001 63503 13-53-000-003 22217 13-53-000-007 10133 13-53-000-008 10616

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.