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 Check.
General Method
- Verify that the leak is transmission fluid.
- Thoroughly clean the suspected leak area.
- Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
- Park the vehicle over clean paper or cardboard.
- Turn the engine OFF.
- Look for fluid spots on the paper.
- Make the necessary repairs.
Powder Method
- Thoroughly clean the suspected leak area with solvent.
- Apply an aerosol type powder, such as foot powder, to the suspected leak area.
- Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.
- Turn the engine OFF.
- Inspect the suspected leak area.
- Trace the leak path through the powder in order to find the source of the leak.
- Make the necessary repairs.
Dye and Black Light Method
A fluid dye and black light kit is available from various tool manufacturers.
- Follow the manufacturer's instructions in order to determine the amount of dye to use.
- Install the dye. Refer to
Transmission Fluid Check.
- Detect the leak with the black light.
- 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 |
| • | Cracking or porosity of the component |
| • | Improper sealant used, where applicable |
Seals
| • | Fluid level/pressure is too high |
| • | Plugged vent or drain-back holes |
| • | 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 oil pan bolts |
| • | Improperly installed or damaged oil pan gasket |
| • | Damaged oil pan or mounting face |
| • | Incorrect oil pan gasket |
Case Leak
| • | 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 |
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 or damaged |
| • | Converter seal garter spring missing from the seal |
| • | Porous casting of the transmission case or the oil pump |
Leak at the Vent
| • | Water or coolant in the fluid. The fluid will appear milky |
| • | Transmission case porous |
| • | Drain-back holes plugged |
| • | Mispositioned oil pump to case gasket, if equipped |
Leak Inspection Points
