A/T - Diagnosing Oil Leaks

Number 83-I-53 Section 7 Date 03/83
Subject: DIAGNOSING TRANSMISSION OIL LEAKS - MODELS 125C, 200C AND 200-4R
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, T.V. cable connector area, and the valve body cover to transmission oil pan interface area on 125C models. (C.R.C.'s electramotive cleanser or equivalent is recommended.)

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

3. After normal operating temperature (170~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 (wetness, moist, damp, etc.), refer to the repair procedure (shown on the reverse side).

FIGURE #1 - THM 200-4R:

FIGURE #2 - THM 200C:

FIGURE #3 - THM 125C:

REPAIR PROCEDURE:

ALL MODELS (See Figures 1, 2 & 3 on following pages)

ITEM PART NAME LEAK CAUSE CORRECTION

2 Transmission Oil Pan Low bolt torque. Retorque and recheck bolts.

Gasket leak. Remove and replace gasket.

Broken R.T.V. bead. Remove cover and reseal with R.T.V.

3 T.V. Cable Connector "C" Connector cocked and interfering Remove connector and reinstall.
with mount.

Seal damaged. Remove and replace seal.

Connector cracked. Remove and replace cable.

Fill Tube "D" Seal missing or damaged. Remove fill tube and replace seal.

Electrical Connector "E" "O" ring missing or damaged. Remove connector and replace seal.

Connector missing or damaged. Remove and replace connector.

4 Manual Shaft Seal assembly damaged. Remove and replace seal.

5 Governor Cover "O" ring damaged. Remove and replace "O" ring.

Low bolt torque. Retorque bolts and recheck.

6 Speedometer Fitting Low bolt torque. Retorque bolt and recheck.

Seal damaged. Remove and replace seal.

7 Servo Cover "O" ring damaged. Remove and replace "O" ring.

8 Cooler Fittings Low fitting torque. Retorque fitting and recheck.

Cracked fitting. Replace and retorque fitting.

11 Converter Assembly Hub or seam weld leak. Remove and replace converter.

12 Converter Seal Seal damaged. Remove and replace seal.

13 Vent Leaking. Check for the following and correct
as necessary:
A) Oil overfill.
B) Blocked drainback holes in sprocket support.
C) Engine coolant in oil.

125-C ONLY (See Figure 3 on last page)

16 Valve Body Cover To Low bolt torque. Retorque bolts and recheck.
Case Assembly
R.T.V. bead broken. Remove cover and reseal with R.T.V.

Gasket leak. Remove gasket and replace.

17 Axle Shaft Seals Seals damaged. Remove seals and replace.

200-C & 200-4R ONLY (See Figures 1 & 2 on following pages)

14 Pump Assembly Pump bolts loose. Retorque bolts and recheck.

Pump "O" ring cut or damaged. Remove "O" ring and replace.

Pump porosity. Replace pump.

15 Rear Extension Seal Torn or damaged. Remove seal and replace.