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Fluid Leak Diagnosis

Fluid Leak Diagnosis

General Method


1. Verify that the leak is transmission fluid.

2.
Warning

Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings.


Thoroughly clean the suspected leak area using a rag.

3.
Note

Do not idle vehicle, this will not actuate transmission systems, and do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.


Operate the vehicle for 15-20 minutes under city driving conditions until normal operating temperatures are reached.

4. Park the vehicle over clean paper or cardboard.

5. Turn OFF the engine.

6. Look for fluid spots on the paper.

7. Make the necessary repairs.


Powder Method


1.
Warning

Do not clean using brake cleaner or other reactive solvents as these solvents can damage rubber gaskets, seals and bushings.


Thoroughly clean the suspected leak area using a rag.

2. Apply an aerosol type leak tracing powder to the suspected leak area.

3.
Note

Do not idle vehicle, this will not actuate transmission systems, and do not drive the vehicle on the freeway as this will splatter oil inhibiting leak diagnosis.


Operate the vehicle for 15-20 minutes under city driving conditions until normal operating temperatures are reached.

4. Turn 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. 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 seal bore

Damaged or worn seal

Improper installation

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 Case Cover and/or Valve Body Cover

Incorrectly tightened bolts

Improperly installed or damaged gasket/seal

Damaged mounting face

Incorrect gasket seal



Case Leak

Damaged input speed sensor seal

Damaged manual shaft seal

Loose or damaged oil cooler lines/seals

Worn or damaged axle shaft oil seal

Loose line pressure pipe plug or fluid level pipe plug

Porous casting

Warped torque converter housing

Damaged converter housing to case seal



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 torque converter housing



Leak at the Vent

Overfilled system

Water or coolant in the fluid. The fluid appears milky.

Transmission case porous

Incorrect fluid level indicator causing an overfilled system

Plugged vent




Leak Inspection Points



(1) Manual Shift Shaft Seal


(2) Automatic Transmission Vent


(3) Control Valve Body Cover Wiring Connector Hole Seal


(4) Input Speed Sensor Seal


(5) Converter Housing to Case Joint


(6) Front Wheel Drive Shaft Oil Seal Assembly - Case


(7) Torque Converter Fluid Seal Assembly


(8) Torque Converter Assembly


(9) Front Wheel Drive Shaft Oil Seal Assembly - Torque Converter Housing


(10) Control Valve Body Cover Assembly Gasket


(11) Fluid Level Hole Plug


(12) Fluid Pressure Hole Plug


(13) Case Cover Gasket