REVISED:TORQUE CONVERT.CLUTCH DIAGNOSIS INFORMATION

Some 1982 THM 125C transmissions may exhibit a "shudder" feel immediately following the torque converter clutch engagement.

In diagnosing this condition, check for the following: (Figure #1)

1. Inspect the turbine shaft seal and "O" ring for damage (distorted, cut, scored, etc.). The "O" ring is located at the long end of the turbine shaft (spline end) with one teflon seal (yellow, larger diameter) located below the converter feed lube holes. Two other teflon seals (yellow, with green speckles) are located at the short end of the shaft. If replacement seals are needed, order service package number 8631968.

2. Inspect the pump shaft seal for damage. (Distorted, cut, scored, etc.)

3. Check the converter clutch control regulator valve in the auxiliary control valve assembly, for freeness.

A new governor pressure switch went into production for diesel models only, in late April, 1982, to correct the "shudder" feel, by raising the converter clutch apply speed. In servicing Diesel model transmissions for this condition, refer to the following chart for proper model usage:

Model Governor Switch No. OP, HU, HY, H6, HR 8643369 HW 8637296 HS 8643368 CD, HI, HC 8643367

Refer to the service manual for proper removal and installation of the seals and governor pressure switch.

Some 1982 THM 125C transmissions may along with the "shudder" feel, experience a no torque converter clutch release condition. In diagnosis of this condition check the auxiliary control valve assembly for the proper location of the solenoid orifice cup plug.

The following conditions could occur: (Figure#2)

1. The solenoid orifice cup plug could be missing or damaged with a hole in it. A no converter clutch release condition would occur.

2. The solenoid orifice cup plug could be installed too far into the bore past the third land in the auxiliary control valve assembly. This would create a "shudder" condition.

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.