TRANS OIL PAN LEAKS THM 700-R4 REVISION INFORMATION

VEHICLES AFFECTED: Vehicles Equipped with 700-R4 Transmissions

Beginning July 25, 1983, a new transmission oil pan (Figure 1) and hex head screw and conical washer assembly (Figure 2) went into production for all THM 700-R4 transmissions.

When servicing any THM 700-R4 transmission for transmission oil pan leaks, the following procedure should be used.

Service Procedure

1. Diagnose source of leak to be certain leak is from the transmission oil pan area. (Refer to 1983 Service Bulletin 7-177 dated Aug. 31/83 for diagnosing transmission oil leaks.)

2. If a leak is determined to be from the transmission oil pan area:

Remove the oil pan and gasket.

Clean the case oil pan face (with solvent) and visually inspect the case oll pan face for damage.

3. Replace the former oil pan, (Figure 1) hex head screws (Figure 2) and gasket with new oil pan (Figure 1) and hex head screw and conical washer assemblies (Figure 2). Order service package 8642999.

The service package contains the following:

1 - New Oil Pan 16 - New Hex Head Screw and conical Washer Assembly 1 - Gasket

These parts are also available separately:

8647498 New Oil Pan 8654095 New Hex Head Screw & Conical Washer Assembly 8642360 Gasket

4. When replacing the oil pan, it is critical that a torque wrench is used to tighten the hex head screws. DO NOT USE IMPACT WRENCH!

Torgue all hex head screws to 11.0 N.m or (9.0 ft. lbs.), then re-torque all the hex head screws a second time to the same specifications as above. The second re-torque is important because the gasket material relaxes after the first tightening.

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.