Methods for Locating Leaks
You can generally locate and repair the cause of most external leaks
with the transmission in the vehicle. Use any one of the following methods
for locating leaks:
General Method
- Verify that the leak is transmission fluid.
- Thoroughly clean the suspected leak area.
- Operate the vehicle for about 15 miles or until you have
reached normal operating temperatures 88°C (190°F).
- Park the vehicle over clean paper or cardboard.
- Shut the engine off and look for fluid spots on the paper.
- Make necessary repairs.
Powder Method
- Thoroughly clean the suspected leak area with a solvent.
- Apply an aerosol type powder such as foot powder to the suspected
leak area.
- Operate the vehicle for about 15 miles or until you have
reached normal operating temperatures 88°C (190°F).
- Shut the engine off.
- Inspect the suspected leak area and trace the leak path through
the powder to find the source.
- Make necessary repairs.
Dye and Black Light Method
- Add dye to the transmission through the transmission fill cap.
Follow the manufacturer's recommendation for the amount of dye to be used.
- Find the leak with a black light.
- Make the necessary repairs.
Repairing the Fluid Leak
Once you have found the leak point, you must next determine the source
of the leak. The following list describes the potential causes for the leak:
| • | Fasteners are not torqued to specification. |
| • | Fastener threads and fastener holes are dirty or corroded. |
| • | Gaskets, seals, or sleeves are misaligned, damaged, or worn. |
| • | Seal bores or gasket surfaces are damaged warped or scratched. |
| • | The manual shaft is nicked or damaged. |
| • | A loose or worn bearing can cause excess seal or sleeve wear. |
| • | Case or component porosity. |
| • | The fluid level is too high. |
| • | A vent is plugged or a vent tube is damaged. |
| • | The fluid contains water or coolant. |
| • | The fluid drain back holes are plugged. |
Possible Points of Oil Leaks
| • | Oil may leak from the transmission or the transmission oil pan
for the following reasons: |
| - | The attaching bolts are not torqued correctly. |
| - | The gasket is damaged or is improperly installed. |
| - | The oil pan or the mounting face is not flat. |
| • | Oil may leak from the case for the following reasons: |
| - | The multi-lip seal on the filler tube is damaged or missing. |
| - | The filler tube bracket is misaligned. |
| - | The speed sensor seal is damaged. |
| - | The manual shaft seal is damaged. |
| - | The connector fittings on the oil cooler are loose or damaged. |
| - | The propeller shaft oil seal is worn or damaged. |
| - | The plug from the line pressure pipe is loose. |
| • | Oil may leak from the converter end for the following reasons: |
| - | The converter seal is damaged. |
| • | The seal lip is cut (check the converter hub for damage). |
| • | The bushing has been moved forward and is damaged. |
| • | A garter spring is missing from the seal. |
| - | The converter is leaking from a weld area. |
| - | A casting is porous in the case or the pump. |
| • | Fluid may come out from the vent pipe or the fill tube under the
following conditions: |
| - | If the fluid appears milky, water or coolant may be in the fluid. |
| - | The fluid level indicator registers incorrectly. |
| - | The drain back holes are plugged. |
| - | The oil pump is misaligned to the case gasket, if equipped. |
Leak Inspection Points
