M/T - Squawk Noise in 5th Gear Cold Only

Number: 93-274-7B
Section: 7B
Date: JULY 1993
Corporate Bulletin No.: 367205
ASE No.: A3

Subject:
SQUAWK NOISE IN 5TH GEAR-COLD ONLY

Model and Year:
1993 S TRUCKS WITH 2.5L OR 2.8L ENGINES AND 5-SPEED MANUAL TRANSMISSION

CONDITION:
Some 1993 S-trucks equipped with a 2.8L (RPO LL2) or a 2.5L (RPO L38) engine and manual 5-speed transmission may exhibit a condition in 5th gear, ONLY WHEN COLD (typically the first 5-10 miles after initial start-up), that sounds like a "dry bearing" squawking type noise.

CAUSE:
The squawking type noise may be due to the input shaft gear blocker ring vibrating on the input shaft.

CORRECTION:
To correct the squawking noise installation of an input shaft blocker ring wave spring (P/N 12545629) is necessary.

SERVICE PROCEDURE:

1. Remove the transmission as outlined in Section 7B, page 4, of the 1993 S-10 Service Manual.





2. Put the transmission into the neutral gear position and drain the oil. Tilt the rear end of the transmission approximately 20 degrees upward (Figure 1).

3. Remove the four (4) front retainer bolts. Remove the front retainer.





NOTE:
The oil seal, shims, and taper bearing cup should remain housed in the retainer (Figure 2).





4. Remove the input shaft from the case by rotating the input shaft until the relief (cut-out) surface on the clutch tooth member of the shaft allows it to clear the countershaft (Figure 3). Pushing the rear mainshaft while withdrawing the input shaft will ease removal.

IMPORTANT:
Do not allow the following parts to fall into case:
- Blocker ring-input shaft cone
- Input shaft roller bearings-15 ct.
- Thrust bearing and thrust washer housed in pocket area of input shaft
If any of these parts accidentally fall into the case, removal of the extension housing and top cover is required for retrieval.





5. Using grease, position the pocket roller bearings (15), thrust washer on input shaft and install the wave spring (P/N 12545629) on the input shaft as illustrated in Figure 4.

6. Carefully install the input shaft assembly into the case.

NOTE:
The wave spring should be sandwiched between the clutch tooth face of the input shaft and the input shaft blocker ring.

7. Thoroughly clean all mating surfaces and apply 3 mm (1/8 in.) bead of RTV sealant (P/N 12345734 or equivalent) to the front bearing retainer.

8. Install the front bearing retainer assembly.

NOTE:
Make sure that the large square oil slot is positioned at the bottom.

9. Torque the front bearing retainer bolts to 15-27 N-m (11-20 lb.ft.).

10. Fill the transmission to its proper level with Dexron II (GM P/N 1051855 or equivalent).

11. Install the transmission as outlined in Section 7B, page 4, of the 1993 S-10 Service Manual.

VEHICLES INVOLVED:





Vehicles built AFTER the VIN Breakpoints (See illustration) are NOT AFFECTED:





SERVICE PARTS INFORMATION:

WARRANTY INFORMATION:
For vehicles repaired under warranty, use:

LABOR 0P: T7656
LABOR TIME: 2.0 Hrs.

NOTE:
Labor operation is coded to base vehicle cover age in the warranty system.