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Fluid Leak Diagnosis

Fluid Leak Diagnosis

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 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 leak tracing 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 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 instructions in order to determine the amount of dye to use.

2. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.

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 or worn seal.

• Cracks in component.

• Manual shaft or output shaft surface is scratched, nicked, or damaged.

• Loose or worn bearing causing excess seal wear.


Possible Points of Fluid Leaks


Transmission Valve Body Cover

• Incorrectly tightened bolts.

• Improperly installed or damaged gasket/seal.

• Damaged mounting face.

• Incorrect gasket seal.



Transmission Case Leak

• Loose or damaged oil cooler lines/seals.

• Worn or damaged axle shaft oil seal.

• Loose line pressure pipe plug or fluid level pipe plug.



Leak at the Transmission Vent

• Overfilled system.

• Water or coolant in the fluid. The fluid will appear milky. Check vent hose mounting.

• Plugged vent.