M/T - Gear Rattle or Knock in Second Gear
Number: 83-T-64Section: VIIb
Date: July, 1983
Subject: GEAR RATTLE OR KNOCK IN SECOND GEAR - 1982-83 "S/T" TRUCKS EQUIPPED WITH BORG WARNER FOUR SPEED MANUAL TRANSMISSIONS (RPO M77)
TO: ALL CHEVROLET DEALERS
Some 1982-83 "S/T" trucks equipped it Borg Warner four speed
manual transmissions may exhibit a "knock" or "rattle" noise while in second 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 the Chevrolet Service Manual, Section 7B 1, or Chevrolet Service "S/T" Truck 77M (four speed) 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.
FIG. 1:
3. Install torsion spring, P/N 14079331, between case and lever in orientation shown in Figure 1 with spring's, long tang positioned in front of web of case.
NOTICE: The view shown in Figure 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.
FIG. 2:
5. Install clip that retains reverse relay lever (and spring) to pivot pin as shown in Figure 2.
FIGURE 3 - TORSION SPRING:
6. Using a suitable tool or hook fashioned similar to the one shown in Figure 3, pull bent tang of torsion spring behind lever and hook end of spring over lever as shown.
7. Following instructions outlined in the Chevrolet Service Manuals. 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