GM Service Manual Online
For 1990-2009 cars only

NEW TRANSAXLE CASE 125,125C INFORMATION

Model and Year 1984 CELEBRITY, CAVALIER AND CITATION

Beginning 1984 production of the THM 125/125C transmissions, a new transmission case went into production. The changes in the 1984 THM 125/125C transmission case are as follows:

CHANGES IN THE 1984 125/125C TRANSMISSION CASE

1. The manual shaft hole was made larger in diameter to accommodate a larger manual shaft.

2. The manual shaft seal bore was made deeper to accommodate a double lip seal.

3. The transmission case casting was changed to accommodate a neutral start switch.

4. The low and reverse snap ring groove was moved toward the cast sprocket face to accommodate thicker low and reverse clutch plates.

NOTICE: The new 1984 THM 125/125C transmission case cannot be used to service any models prior to the 1984 models. The past style transmission case (1983 model or earlier) cannot be used to service the 1984 THM 125/125C transmission.

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.