NEW DESIGN TORQUE CONVERTER SERVICE PARTS

VEHICLES AFFECTED: THOSE VEHICLES EQUIPPED WITH THM 125 TRANSMISSION IN 1982 ALL THM 125 AND THM 125C TRANSMISSIONS WILL BE BUILT WITH A NEW DESIGN 245MM TORQUE CONVERTER IN PLACE OF THE PAST DESIGN 254MM TORQUE CONVERTER. THE 245MM TORQUE CONVERTER WILL REQUIRE A NEW DESIGN TURBINE SHAFT, CONVERTER HOUSING OIL SEAL AND AN OIL PUMP DRIVE SHAFT. THE SPLINE OF THE NEW DESIGN TURBINE SHAFT IS 5.1MM LONGER THAN THE PAST DESIGN AND HAS AN 'O' RING SEAL GROOVE. SEE FIGURE 1. FIGURE 1 TURBINE SHAFT THE NEW DESIGN CONVERTER HOUSING OIL SEAL CAN BE IDENTIFIED BY PART NUMBER 8637420 ON THE SEAL. THE PAST DESIGN CONVERTER HOUSING OIL SEAL WILL EITHER HAVE NO IDENTIFICATION NUMBER OR WILL HAVE PART NUMBER 8631158 ON THE SEAL. SEE FIGURE #2. FIGURE 2 CONVERTER HOUSING OIL SEAL THE NEW DESIGN OIL PUMP DRIVE SHAFT IS 23.7MM LONGER THAN THE PAST DESIGN AND HAD 15 TEETH ON THE OIL PUMP SPLINE INSTEAD OF THE PAST DESIGNS 20 TEETH. SEE FIGURE 3.

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.