Leakage Inspection
Leakage Inspection
NOTICE: Do not try to stop the transmission fluid leak by increasing the torque beyond specifications. This may cause damage to the case threads.
Check the transmission fluid filler tube at the transaxle case. If leakage is found here, install a new plug.
Check transmission fluid cooler tubes and fittings between the transaxle and the transmission fluid cooler for looseness, wear or damage. If leakage cannot be stopped by tightening a transmission fluid tube nut, install new parts.
If the leak continues, install a new transmission fluid cooler tube fitting and tighten to specification. The same procedure should be followed for transmission fluid leaks between the transmission fluid cooler and the transmission fluid cooler tube fittings.
The transmission fluid cooler can be further checked for leaks.
If leakage is found at the Transmission Range (TR) manual control lever, install a new seal.
If leakage is found at the transaxle harness connector, install a new O-ring.
The transaxle has the following parts to prevent external fluid leakage:
- Sealer
- Lip-type seals
- O-ring seals
- Seal rings
- Seal grommets
- Thread sealant
- Transmission fluid pan
External Sealing
Transmission Fluid Leakage in Torque Converter Area
In diagnosing and correcting transmission fluid leaks in the pump support and gear and torque converter area, use the following procedures to locate the exact cause of the leakage. Leakage between the transaxle and engine, as evidenced by fluid around the torque converter housing, may have several sources. By careful observation it is possible, in many instances, to pinpoint the source of leakage before removing the transaxle from the vehicle. The paths which the fluid takes to reach the bottom of the torque converter housing are shown in the illustration. The 5 steps following correspond with the numbers in the illustration.
1. Transmission fluid leaking by the pump seal lip will tend to move along the impeller hub and onto the back of the impeller housing. Except in the case of a total seal failure, transmission fluid leakage by the lip of the seal will be deposited on the inside of the torque converter housing only, near the outside diameter of the housing. Transmission fluid from the vent assembly may move along the impeller hub and onto the back of the impeller housing. Transmission fluid from a converter hub weld leak will move along a path on the inside of the converter housing.
2. Transmission fluid leakage by the outside diameter of the pump seal and pump body will follow the same path that leaks by the inside diameter of the pump seal follow. Transmission fluid from a converter hub weld leak will move along a path on the inside of the converter housing.
3. Transmission fluid that leaks by a pump-to-case screw or pump gasket will be deposited on the inside of the torque converter housing only. Transmission fluid will not be deposited on the back of the torque converter.
4. Transmission fluid leakage from the converter drain plug, (model-dependent) converter seal weld or converter-to-flexplate stud weld will appear at the outside diameter of the torque converter on the back face of the flexplate, and in the converter housing only near the flexplate. Transmission fluid leaks from the torque converter will leave a ring of transmission fluid around the inside of the torque converter housing.
5. NOTE: White facial tissue paper may aid in determining the color (red is transmission fluid) and source of the leaking transmission fluid.
Engine oil leaks are sometimes incorrectly diagnosed as transaxle pump gasket leaks. The following areas of possible leakage should also be checked to determine if engine oil leakage is causing the concern.
a. Leakage at the valve cover gasket may allow oil to flow over the torque converter housing or seep down between the torque converter housing and cylinder block causing oil to be present in or at the bottom of the torque converter housing.
b. Oil galley plug leaks will allow oil to flow down the rear face of the cylinder block to the bottom of the torque converter housing.
c. Leakage at the crankshaft rear oil seal will work back to the flexplate, and then into the torque converter housing.
Leak Check Test
1. Original factory fill transmission fluid is dyed red to aid in determining if leakage is from the engine or transaxle. The red color should assist in pinpointing the leak.
2. Clean off any fluid from the top and bottom of the torque converter housing of the case, and the rear face of the engine and oil pan. Clean the torque converter area by washing with a suitable nonflammable solvent and blow dry with compressed air.
3. Wash out the torque converter housing, and the front of the flexplate. The torque converter housing may be washed out using cleaning solvent and a squirt-type oil can. Blow all washed areas dry with compressed air.
4. Start and run the engine until the transaxle reaches its normal operating temperature. Observe the back of the cylinder block and the top of the torque converter housing for evidence of fluid leakage. With the vehicle in NEUTRAL, position it on a hoist. Refer to Maintenance/Service and Repair and run the engine at fast idle, then at engine idle, occasionally shifting to the D and R positions to increase pressure within the transaxle.
Observe the front of the flexplate, back of the cylinder block (in as far as possible), and inside the torque converter housing and front of the case.
Leak Check Test With Black Light
Dye-Lite(R) ATF/Power Steering Fluid Leak Detection Dye 164-R3701 or equivalent (specifically formulated for ATF) is used to detect a transmission fluid leak.
1. Add Automatic Transmission/Power Steering Dye to the transmission fluid. Use one 30.0 mL (1oz) of dye solution for every 3.8L (4 qt) of transmission fluid.
2. Start and run the engine until the transaxle reaches its normal operating temperature. Observe the back of the cylinder block and top of the torque converter housing for evidence of fluid leakage. Raise the vehicle on a hoist and run the engine at fast idle, then at engine idle, occasionally shifting to the DRIVE and REVERSE ranges to increase pressure within the transaxle. Observe the front of the flexplate, back of the cylinder block (in as far as possible), and inside the torque converter housing and front of the case. Continue running the engine until fluid leakage is evident and the probable source of leakage can be determined.