Leakage Inspection
Leakage Inspection
NOTICE: Do not try to stop the fluid leak by increasing the torque beyond specifications. This may cause damage to the case threads.
Leakage at the transaxle main control cover-to-transaxle often can be stopped by tightening the attaching bolts to 12 Nm (106 lb-in). If necessary, remove the main control cover and inspect for damage. Refer to Main Control Cover Service and Repair.
Check the transmission fluid filler tube connection at the transmission case. If leakage is found here, install a new grommet.
Check transmission fluid tubes and fittings between the transmission and the cooler in the radiator tank for wear or damage. When transmission fluid is found leaking between the case and the transmission fluid cooler tube fitting, check for a missing or damaged O-ring, then tighten the fitting to torque specification.
If the leak continues, install a new transmission fluid cooler tube fitting and tighten to the correct torque specification. The same procedure should be followed for transmission fluid leaks between the radiator cooler and the transmission fluid cooler tube fittings. Refer to Transmission Cooler, A/T.
Check the engine coolant in the radiator. If the transmission fluid is present in the coolant, the cooler in the radiator is probably leaking. The cooler can be further checked for leaks by disconnecting the transmission fluid cooler tubes from the cooler fittings and applying no more than 345 kPa (50 psi) air pressure to the fittings. Remove the coolant recovery cap to relieve the pressure buildup at the exterior of the transmission fluid cooler tank. If the cooler is leaking and/or will not hold pressure, install a new cooler.
If transmission fluid leakage is found at the transaxle range selector lever, install a new seal.
If transmission fluid leakage is found at the transaxle internal harness connector, install a new O-ring.
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 transaxle, 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 the leak 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 converter hub seal lip will tend to move along the drive hub and onto the back of the torque converter. 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 OD of the housing.
2. Transmission fluid leakage by the OD of the converter impeller hub seal and the case will follow the same path that leaks by the ID of the converter hub seal follow.
3. Transmission fluid leakage from the converter cover weld or the converter-to-flexplate stud weld will appear at OD of torque converter on the back face of the flexplate and in the converter housing only near the flexplate. If a converter-to-flexplate lug, lug weld or converter cover weld leak is suspected, remove the converter and pressure check.
4. Transmission fluid leakage from the bolts inside the converter housing will flow down the back of the torque converter housing. Leakage may be from loose or missing bolts.
5. Engine oil leaks are sometimes incorrectly diagnosed as transaxle converter hub seal leaks. The following areas of possible leakage should also be checked to determine if engine oil leakage is causing the concern.
1. Leakage at the valve cover gasket may allow engine 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.
2. Oil galley plug leaks will allow engine oil to flow down the rear face of the cylinder block to the bottom of the torque converter housing.
3. Leakage at the crankshaft rear oil seal will work back to the flexplate, and then into the torque converter housing.
4. Leakage at oil pressure sensor will allow engine oil to flow down the rear face of the cylinder block to the bottom of the torque converter housing.
Leak Check Test
1. Remove the transmission fluid level indicator and note the color of the transmission fluid. Original factory fill transmission fluid is dyed red to aid in determining if leakage is from the engine or transaxle. Unless a considerable amount of makeup transmission fluid has been added or the transmission fluid has been changed, the red color should assist in pinpointing the leak.
2. Remove the torque converter housing cover. Clean off any transmission fluid from the top and bottom of the torque converter housing, the front of the case and 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, the front of the flexplate and the converter drain plugs. 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 top of the torque converter housing for evidence of transmission fluid leakage. Raise the vehicle on a hoist and run the engine at fast idle, then at engine idle, occasionally shifting to the OVERDRIVE 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. Run the engine until transmission fluid leakage is evident and the probable source of leakage can be determined.
Leak Check Test With Black Light
Dye-Lite(R) ATF/Power Steering Fluid Leak Detection Dye 164-R3701 (Rotunda) is used to detect a transmission fluid leak.
1. Add Dye-Lite(R) ATF/Power Steering Fluid Leak Detection Dye to the transmission fluid. Use one 30 ml (1 oz) bottle 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 using the 100W/12 Volt DC UV Lamp, 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), inside the torque converter housing and the entire case until fluid leakage is evident and the probable source of leakage can be determined.