For 1990-2009 cars

# THRUST BEARING ASSEMBLY 125 AND 125C TRANSMISSIONS

#### MODELS AFFECTED: ALL 1980 THRU 1984 THM 125/125-C

Since October, 1983 a new larger thrust bearing assembly (final drive sun gear to differential carrier) went into production in the 1984 model THM 125/125C transmission, using the 2.84 ratio final drive and differential assembly.

The difference between the two thrust bearing assemblies is the outer diameter size. Also the carrier bearing surface is machined larger to accommodate the larger outer diameter bearing. Thrust bearing 8646254 (figure 1) is larger than thrust bearing 8628962 (figure 2).

The two thrust bearing assemblies are not interchangeable and damage to the final drive could result if the bearings are mixed. To assure correct usage refer to the following service procedure.

#### Service Procedure:

1. After removing the thrust bearing assembly from the final drive differential carrier measure the outer diameter using a standard ruler as shown in figures 1 & 2.

2. If the outer diameter is 2-1/8" order service package 8646254. If the outer diameter is 2" order part 8628962.

#### NOTE: The larger thrust bearing assembly part number 8646254, was previously used on only the 3.06 and 3.33 ratio final drive assemblies, but now is used on all models.

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.