VEHICLES AFFECTED: VEHICLES EQUIPPED WITH THM 125-C,
200-C, 325-4L, AND 200-4R TRANSMISSIONS
WHEN ANY THM TRANSMISSION OIL LEAK IS DETECTED, IT IS VERY
IMPORTANT THAT THEY ARE DIAGNOSED PROPERLY, AS TO LOCATION AND
TYPE OF LEAK.
THE FOLLOWING PROCEDURE WILL HELP IN DIAGNOSING THE TYPE AND
LOCATION OF THE LEAK AND WILL SUGGEST A CORRECTION METHOD.
DIAGNOSIS PROCEDURE: (ALL MODELS)
THE FOLLOWING PROCEDURE CAN BE PERFORMED ON CAR.
1. CLEAN ALL RESIDUAL OIL FROM THE TRANSMISSION, CONCENTRATING ON
THE TRANS. OIL PAN TO CASE MATING AREA (ALL MODELS), T.V. CABLE
CONNECTOR (ALL MODELS), TRANS OIL PAN TO SPROCKET
COVER INTERFACE AREA (325-4L MODEL), FINAL DRIVE TO CASE
CONNECTION (325-4L MODEL), AND VALVE BODY COVER TO TRANS.
OIL PAN INTERFACE AREA (125C MODEL) (ENGINE SHAMPOO P/N 992878
OR EQUIVALENT IS RECOMMENDED).
2. DUST THE ENTIRE TRANSMISSION WITH A WHITE POWDER.
3. AFTER NORMAL OPERATING TEMPERATURE 76 DEGREES C (170 DEGREES F)
HAS BEEN OBTAINED, LET THE TRANSMISSION STAND FOR AT LEAST 30
MINUTES.
4. INSPECT THE TRANSMISSION FOR LEAKAGE BY FOLLOWING RED OIL
TRACES LEFT IN THE POWDER. (IF RESIDUAL OIL IS LEFT ON THE
TRANSMISSION OIL PAN OR SPROCKET COVER, IT WILL NECESSITATE
THE CLEANING AND DUSTING PROCEDURE TO BE REPEATED.)
5. ONCE THE LEAK HAS BEEN DIAGNOSED AS TO LOCATION AND TYPE
REFER TO THE FOLLOWING REPAIR PROCEDURE.(**SEE BULLETIN**)
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.