A/T- 3T40 New Side Cover and Bottom Pan Gasket
90buick13Bulletin 91-7125-3
Date Oct. '90
Ref. No. 91-040-7125
Corp. Ref. No. 077132
Figure 1:
SUBJECT: NEW SILICONE BEADED SIDE COVER AND BOTTOM PAN GASKET
MODELS AFFECTED: 1980-91 ALL MODELS WITH 3T40 (THM 125C) TRANSAXLE
BULLETIN COVERS:
A new Side Cover gasket and Bottom Pan gasket for all Hydra-Matic 3T40 (THM 125C) transaxles, which reduces the potential for Side Cover and/or Bottom Pan leaks. These new gaskets are light gray in color and can be identified by a Silicone Bead which is dark orange in color. (Figure 1)
DATE OF PRODUCTION CHANGE:
These new Gaskets went into production July 16, 1990 (Julian Date 197) for all Hydra-Matic 3T40 (THM 125C) transaxles.
SERVICE PROCEDURE:
These new gaskets can be used on all previous model Hydra-Matic 3T40 (THM 125C) transaxles. Whenever installation or replacement of this new gasket is necessary, refer to the following procedure.
SIDE COVER GASKET:
1. Clean ribbed surface of side cover and machined surface of case where gasket is to be installed. Both surfaces MUST be free of transmission fluid.
2. Place side cover gasket on case with silicone bead facing out.
3. Carefully install side cover onto gasket and install all pan bolts (7) by hand.
IMPORTANT: The rib on the pan must fully contact the entire silicone bead; if it does not, leakage may occur.
4. Torque all pan bolts to 11 N-m (98 lbs.in.).
BOTTOM PAN GASKET:
1. Clean ribbed surface of bottom pan and machined surface of case where gasket is to be installed. Both surfaces MUST be free of transmission fluid.
2. Place bottom pan gasket on case with silicone bead facing out.
3. Carefully install bottom pan onto gasket and install all pan bolts by hand.
IMPORTANT: The rib on the pan must fully contact the entire silicone bead; if it does not, leakage may occur.
4. Torque all pan bolts to 11 N-m (98 lbs.in.).
SERVICE PARTS INFORMATION:
Whenever ordering this new silicone beaded gasket, refer to the following part numbers:
Part Number Description
8678169 Side Cover Gasket
8678168 Bottom Pan Gasket
All Hydra-Matic 3T40 service packages that contain Side Cover and Bottom Pan gaskets have been updated to include the new Silicone Beaded gaskets.
Parts are now available from GMSPO.
SERVICE MANUAL REFERENCE:
Whenever replacement and/or installation of a Side Cover or Bottom Pan gasket on any Hydra-Matic 3T40 is necessary, refer to the Unit Repair Section of your Service Manual.