DELAYED ENGAGEMENT-THM 325 AND THM 325-4L

VEHICLES AFFECTED: All 1979-85 with THM 325 or THM 325-4L Transmissions

Some 1979 through 1981 THM 325 and some 1982 through 1985 THM 25-4L transmissions may experience a delayed engagement. This condition may be caused by a loss of pump prime due to oil raindown in the pump.

This condition can be repaired by installing a new valve and sleeve assembly (Figure 1-B) in the case pump intake hole.

When servicing any of the above transmissions for delayed engagement order service package 8635971 and follow the service procedure given below.

Service Procedure:

1. Remove the transmission oil pan and oil screen. Make sure that the transmission oil screen 'O' ring is also removed from the pump intake hole in the transmission case.

2. Install the new valve and sleeve assembly into the case pump intake hole (Figure 1-A) using a 1/2 inch deep well socket on a 3/8 inch extension. Carefully drive the valve and sleeve assembly into the pump intake hole with a small hammer.

3. Reassemble the transmission following service manual procedures.

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.