THM TRANS OIL LEAKS USE TRACING POWDER/FIND LEAK

When any THM transmission oil leak is detected, it is very important that they are diagnosed properly, as to the 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 transmission oil pan to case mating areas (all models), T.V. cable connector (all models), and valve body cover to transmission oil pan interface area (125C model) (C.R.C.'s electramotive cleanser, or equivalent is recommended).

2. Dust the entire transmission with a white powder (e.g. leak tracing powder or foot powder spray).

3. After normal operating temperature (170 DEG F) has been obtained, let the transmission stand for at least thirty (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 (wetness, moist, damp, etc.), refer to the following repair procedure.

REPAIR PROCEDURE - ALL MODELS (FIGURES 2, 3 AND 4)

ITEM PART NAME LEAK CAUSE CORRECTION

2 Transmission Oil Low Bolt Torque Retorque & Recheck Pan Bolts.

Gasket Leak Remove and Replace Gasket Broken R.T.V. Bead Remove Cover and Reseal With R.T.V.

3 T.V. Cable Con- Connector Cocked Remove Connector nector "C" and Interfering and Reinstall with Mount Remove and Replace Seal Damaged Seal

Connector Cracked Remove and Replace Cable

Fill Tube "D" Seal missing or Remove Fill Tube & Damaged Replace Seal

Electrical Con- "O" Ring Missing Remove Connector & nector "E" or Damaged Replace Seal

Connector Missing Remove and Replace or Damaged Connector

4 Manual Shaft Seal Assembly Remove and Replace Damaged Seal

5 Governor Cover "O" Ring Damaged Remove and Replace "O" Ring

Retorque Bolts & Low Bolt Torque Recheck 6 Speedo Fitting Low Bolt Torque Retorque Bolts & Recheck

Remove and Replace Seal Damaged Seal

7 Servo Cover Remove and Replace "O" Ring Damaged "O" Ring

8 Cooler Fittings Low Fitting Torque Retorque Fitting and Recheck

Cracked Fitting Replace & Retorque Fitting

11 Converter Asm. Hub or Seam Weld Remove and Replace Leak Converter

12 Converter Seal Seal Damaged Remove and Replace Seal

13 Vent Leaking Check for the Fol- lowing & Correct as Necessary:

A. Oil overfill

B. Blocked Drain- back Holes in Sprocket Sup- port.

C. Engine Coolant in Oil.

125C ONLY (FIGURE 4)

16 Valve Body Cover Low Bolt Torque Retorque Bolts and to Case Assembly Recheck

R.T.V. Bead Remove Cover & Re- Broken seal With R.T.V.

Gasket Leak Remove Gasket and Replace

17 Axle Shaft Seals Seals Damaged Remove Seals and Replace

200C AND 200-4R ONLY (FIGURES 2 AND 3)

14 Pump Assembly Pump Bolts Loose Retorque Bolts and Recheck

Pump "O" Ring Cut Remove "O" Ring and or Damaged Replace

Pump Porosity Replace Pump 15 Rear Extension Torn or Damaged Remove Seal and Seal Replace

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.