A/T - Whining Noise/Slow/Slipping Engagement
Number: 84-210Section: 7A (VIIc)
Date: Oct., 1984
Subject: WHINING NOISE AND/OR SLOW OR SLIPPING ENGAGEMENT
Model and Year: 1982-84 CHEVETTES WITH THM 180C TRANSMISSIONS
TO: ALL CHEVROLET DEALERS
This cancels and replaces Chevrolet Dealer Service Bulletin 83-101 dated February, 1984, which should be destroyed.
Fig 1. Model, Transmission ID AND Transmission Serial Numbers:
Some THM 180C transmissions built before serial number TP 2928976 (Figure 1) may exhibit a whining noise and/or slow or slipping engagement in all ranges. The noise increases when the engine RPM is increased. This whining noise is similar to noise caused from the steering wheel being turned to its maximum travel..
If the above condition is experienced, check the transmission oil line pressure. (Refer to the service manual for procedure). If the line pressure is low, refer to the following service procedure.
SERVICE PROCEDURE
1. Remove the oil filter and visually inspect for restriction.
2. If the oil filter is restricted, remove the transmission from the vehicle, and remove the pump.
3. After removing the pump, inspect the selective end play washer for wear especially on the inside diameter of the washer. If the washer is worn, replace the oil pump assembly and selective end play washer, using service package 96040245. This package contains the pump assembly and selective end play washers.
4. If the oil filter is not restricted, refer to the proper service manual for additional diagnostic procedures.
Fig 2. End Play Washer:
Starting March 22, 1984, serial number 2928976, a new oil pump assembly and selective end play washer, went into production on all THM 180C transmissions. The new oil pump assembly has a casting change to accommodate the new selective end play washer. The new end play washer (Figure 2) has three (3) raised tabs to hold the washer stationary on the pump.
NOTICE: The new end play washer is not interchangeable with the past oil pump assembly.