This bulletin is being reissued to correct the name "Bearing Assembly" as shown in the illustration (page 2) to "Driven Sprocket Roller Cage Bearing". Also indicated is the correct location on the illustration.
Some 1982 and 1983 THM 125C transmissions may experience a noise condition, best described as a high pitched whine.
This noise condition, if only noticeable in park or neutral, and not in drive or reverse (while stopped with the brakes applied) could be caused from one or more of the following bearings:
(see illustration)
1. Drive Sprocket Roller Cage Bearing 2. Driven Sprocket Roller Cage Bearing 3. Driven Sprocket Thrust Bearing
When servicing any 1982 or 1983 THM 125C for this bearing noise, first inspect the drive and driven sprocket roller cage bearings and driven sprocket thrust bearing for wear or damage. If wear or damage is visable on any of the above bearings, replace them with service parts listed below:
1. Drive Sprocket Roller Cage Bearing - 8631186 2. Driven Sprocket Roller Cage Bearing - 8631190 3. Driven Sprcket Thrust Bearing - 9436851
Refer to your service manual for removal and installation procedures of the drive and driven sprocket support cage bearing.
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.