TRANS OIL PAN LEAKS THM 700-R4 REVISION INFORMATION

MODELS: 1982-1983 LIGHT DUTY TRUCKS WITH THM 700-R4 TRANSMISSION

Beginning July 25, 1983, a new transmission oil pan (Fixure No. 1) and hex head screw and conical washer assembly (Figure No. 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 Service Bulletin 83-B-111 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 oil pan face for damage.

3. Replace the former oil pan, (Figure No. 1) hex head screws (Figure No. 2) and gasket with new oil pan (Figure No. 1) and hex head screw and conical washer assemblies (Figure No. 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

The parts are also available separately.

8654095 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!

Torque 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.