A/T - THM 200-R4 Fluid leaks
Number: 84-104Section: 7A (VIIc)
Oate: April, 1984
Subject: TRANSMISSION OIL PAN, GASKET, AND BOLTS
Model and Year: ALL 200-4R
TO: ALL CHEVROLET DEALERS
FIGURE 1 - TRANSMISSION OIL PAN:
FIGURE 2 - HEX HEAD SCREW AND CONICAL WASHER ASSEMBLY:
Beginning January 3, 1984, all THM 200-4R transmissions are being produced using a new transmission oil pan (Figure 1) , cork gasket, and special hex head bolts with conical washers (Figure 2). The new transmission oil pan has a continuous ribbed flange (Figure 1) to reduce transmission oil leaks..
When servicing any THM 200-4R transmission for transmission oil pan leaks, refer to the following procedure:
SERVICE PROCEDURE
1. Diagnose source of leak to be certain leak is from the transmission oil pan.
2. If a leak is determined to be from the transmission oil pan area:
A. Remove the oil pan.
B. Clean the case oil pan face (with solvent) and visually inspect the case oil pan surface for damage and/or presence of RTV sealant (room temperature vulcanizing sealant).
C. Make sure all RTV sealant is removed from the case oil pan face.
3. Replace the past transmission oil pan, with service package number 8639907 which contains the following:
P/N Quantity Description
8639556 1 Transmission Oil Pan
8634198 1 Gasket Transmission Oil Pan
8643693 16 Bolt Asm., With Conical Washer
4. When replacing the oil pan, it is critical that a torque wrench is used to tighten the hex head screw DO NOT USE
IMPACT WRENCH!
Torque all hex head screws to 11 N.m or (9 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.