A/T - Oil Pan Leaks
Number: 84-69Section: 7A (VIIc)
Date: Feb., 1984
Subject: OIL PAN LEAKS ON THM 700-R4 TRANSMISSIONS
Model and Year: ALL MODEL YEARS - PASSENGER VEHICLES AND TRUCKS
TO: ALL CHEVROLET DEALERS
FIGURE 1 - TRANSMISSION OIL PAN:
FIGURE 2 - HEX HEAD SCREW AND CONICAL WASHER ASSEMBLY:
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 Service Bulletin 83-I-95 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 visual inspect the case oil pan face for damage.
FIGURE 1 - TRANSMISSION OIL PAN:
FIGURE 2 - HEX HEAD SCREW AND CONICAL WASHER ASSEMBLY:
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:
P/N 8647498 New Oil Pan
P/N 8654095 New Hex Head Screw & Conical Washer
Assembly
P/N 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 (9.0 ft. lbs.), then retorque all the hex head screws a second time to the same specifications as above. The second retorque is important because the gasket material relaxes after the first tightening.