SQUEAK NOISE FROM SHIFT LEVER INSPECTION/REPAIR PROCEDURE

TRANSMISSION APPLICATIONS: 1991 S/T TRUCKS WITH 4L60 AUTOMATIC TRANSMISSION

SUBJECT: SQUEAK NOISE FROM SHIFT LEVER (SERVICE PARTS INFORMATION)

TRANSMISSION MODELS:

VEHICLE APPLICATIONS: 1991 S/T TRUCKS WITH A/T

Some customers may comment about a "squeak", "buzz", or "tizzle" noise when driving a 1991 S/T truck with the 4L60 automatic transmission. A possible cause of the noise has been found at the interface of the transmission shift lever and the transmission control lever.

One source of the noise may be a loose fitting of the transmission control lever to the transmission shift lever. This can generate a vibration induced noise. The addition of a wave washer (as described below in the service procedure) may eliminate this condition. The wave washer (P/N 4722812) will prevent the slight perpendicular movement of the shift lever against the control lever which can cause the noise.

T Trucks only (4wd)

A second source of the noise is a possible ground out of the shift lever with the end of the slot in the control lever. This condition can be corrected by the addition of washer (P/N 14074908) to the end of the shift lever which is secured to the frame. At the same time the wave washer is installed, adding washer 14074908 will centre the shift lever in the slot in the control lever preventing the ground out condition. To install washer 14074908 simply remove the retaining pin on the end of the shift lever that is secured to the frame, place the washer over the lever end and replace the retaining pin (this is given as an optional step in the service procedure).

VEHICLES INVOLVED:

Trucks built after the following VIN breakpoints have had the new washer installed in production.

Pontiac West GMC Truck 1GTCS19RXM0526141 Chevrolet 1GCCT14Z6M0189004

Moraine GMC Truck 1GNDT13Z6M2507024 Oldsmobile 1GHDT13Z2M2704746 Chevrolet 1GNDT13Z8M2270913

Shreveport GMC Truck 1GKCT18Zlm8537954 Chevrolet 1GCCS19ZXM8245619

SERVICE PROCEDURE: Refer to Figure 1 ------------------------------------ 1. Apply the parking brake. 2. Disconnect the negative battery cable. 3. Remove retaining pins (10) from each end of the transmission control lever. 4. Separate transmission control lever from the transmission shift lever and insert 1-2 wave washers 4722812, as shown in Figure 2

*NOTE: For T trucks 1-2 washers 14074908 (Figure 3) should be installed to the opposite end of the shift lever at this time (if necessary) Refer to Figure 5.

5. Reinstall transmission control lever into transmission shift lever and install NEW retaining pins. 6. Adjust shift linkage. 7. Reconnect negative battery cable.

SERVICE PARTS INFORMATION:

Part Number Description Quantity ----------- ----------- -------- 4722812 wave washer 1-2 14074908 washer 1-2

Parts are currently available from CANSPO.

NOTE: equivalent wave washer for P/N 4722812 may be obtained locally if the following dimensions are met (Figure 2):

Inside diameter (A) - 0.6 inches + 0.005 inches (15.24 mm + 0.127 mm)

Outside diameter (B) - 0.87 inches (22 mm)

Thickness of wave (C) - 0.017 inches (0.43 mm)

Peak to Peak wave distance (D) - 0.09 inches (2.286 mm)

Washer must be of hardened variety.

**NOTE: equivalent washer for P/N 14074908 may be obtained locally if the dimensions shown in Figure 3 are met.

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.