Fluid Leakage In Torque Converter Area

In diagnosing and correcting fluid leaks in the torque converter area, use the following procedures to locate the exact cause of the leakage. Leakage at the front of the transmission, evidenced by fluid around the converter housing, can have several sources. By careful observation it is possible, in many instances, to pinpoint the source of the leak before removing the transmission from the vehicle. The paths that the fluid can take to reach the bottom of the converter housing are as shown in the following illustration. The following five steps correspond with the numbers in the illustration.

1. Fluid leaking by the torque converter impeller hub seal lip will tend to move along the converter impeller hub and onto the back of the impeller housing. Except in the case of a total seal failure, fluid leakage by the lip of the seal will be deposited on the inside of the converter housing only, near the outside diameter of the converter housing.
2. Fluid leakage by the outside diameter of the converter hub seal and the case will follow the same path the leaks by the inside diameter of the seal follow.
3. Fluid leakage from the torque converter to the flywheel stud weld, drain plug or seal weld will appear at the outer diameter of the torque converter on the back face of the flywheel, and in the converter housing only near the flywheel. If a converter leak is suspected, remove torque converter and pressure check.
4. Fluid leakage from the pump will flow down the back of the converter housing. Leakage can be from any or all of the following: loose or missing pump bolts, torn or damaged pump-to-case gasket, front pump square cut seal, worn pump bushing.
5. Engine oil leaks are sometimes improperly diagnosed as transmission pump seal leaks. The following areas of possible leakage should also be checked to determine if engine oil leakage is causing the condition.
- Leakage at the valve cover may allow engine oil to flow over the converter housing or seep down between the converter housing and block, causing oil to be present in or at the bottom of the converter housing.
- Oil plug leaks will allow oil to flow down the rear face of the block to the converter housing.
- Leakage at the crankshaft seal will work back to the flywheel, and then into the converter housing.