Fluid Leak Diagnosis

Fluid Leak Diagnosis

Notice: The transmission fluid level must be checked before fluid leak diagnosis is performed to prevent damage to the transmission.

Check transmission fluid lever. Refer to Transmission Fluid Checking. Transmission Fluid Check

General Method

1. Verify that the leak is transmission fluid.
2. Thoroughly clean the suspected leak area.
3. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
4. Park the vehicle over clean paper or cardboard.
5. Shut OFF the engine.
6. Look for fluid spots on the paper.
7. Make the necessary repairs.

Powder Method

1. Thoroughly clean the suspected leak area with solvent.
2. Apply an aerosol type powder, such as foot powder, to the suspected leak area.
3. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
4. Shut OFF the engine.
5. Inspect the suspected leak area.
6. Trace the leak path through the powder in order to find the source of the leak.
7. Make the necessary repairs.

Dye and Black Light Method

A fluid dye and black light kit is available from various tool manufacturers.

1. Follow the manufacturer's instructions in order to determine the amount of dye to use.
2. Install the dye. Refer to Transmission Fluid Checking. Transmission Fluid Check
3. Detect the leak with the black light.
4. Make the necessary repairs.

Find the Cause of the Leak

Pinpoint the leak and trace the leak back to the source. You must determine the cause of the leak in order to repair the leak properly. For example, if you replace a gasket, but the sealing flange is bent, the new gasket will not repair the leak. You must also repair the bent flange. Before you attempt to repair a leak, check for the following conditions, and make repairs as necessary:

Gaskets

* Fluid level/pressure is too high
* Plugged vent or drain-back holes
* Improperly tightened fasteners
* Dirty or damaged threads
* Warped flanges or sealing surface
* Scratches, burrs, or other damage to the sealing surface
* Damaged or worn gasket
* Cracking or porosity of the component
* Improper sealant used, where applicable
* Incorrect gasket

Seals

* Fluid level/pressure is too high
* Plugged vent or drain-back holes
* Damaged seal bore
* Damaged or worn seal
* Improper installation
* Cracks in component
* Manual or output shaft surface is scratched, nicked, or damaged
* Loose or worn bearing causing excess seal wear

Possible Points of Fluid Leaks

Transmission Oil Pan

* Incorrectly tightened fluid pan bolts
* Improperly installed or damaged fluid pan gasket
* Damaged fluid pan or mounting face
* Incorrect fluid pan gasket
* Fluid Drain Plug

Case Leak

* Fluid Fill Plug
* Extension Housing
* Wiring harness O-ring seal
* Damaged manual shaft seal
* Loose or damaged fluid cooler line seals fittings
* Worn or damaged propeller shaft flange seal
* Loose line pressure test plug
* Porous casting
* Fluid fill plug

Leak at the Torque Converter End

* Converter leak in the weld area
* Converter seal lip cut. Check the converter hub for damage
* Converter seal bushing moved forward and damaged
* Converter seal garter spring missing from the seal
* Porous casting of the transmission case or the oil pump

Leak at the Vent

* Overfilled system
* Water or coolant in the fluid. The fluid will appear milky
* Transmission case porous
* Plugged vent
* Drain-back holes plugged
* Mispositioned oil pump to case gasket, if equipped

Leak Inspection Points

Leak Inspection Points:

1 - Torque Converter Assembly
2 - Fluid Cooler Pipe Connectors
4 - Torque Converter Housing Fluid Seal Assembly
24 - Automatic Transmission Case Assembly
25 - Case Extension Gasket
29 - Prop Shaft Flange Seal
36 - Transmission Level Hole Plug
40 - Transmission Pressure Test Plug
56 - Automatic Transmission Wiring Harness O-ring Seal
60 - Automatic Transmission Fluid Pan Gasket
63 - Automatic Transmission Fluid Drain Plug
229 - Torque Converter Housing Seal
243 - Transmission Vent Assembly
605 - Manual Shift Shaft Seal
614 - Cup Plug