Leakage Inspection
Leakage Inspection
The transmission has the following parts to prevent external fluid leakage:
- Gaskets
- Lip-type seals
- O-ring seals
- Seal rings
- Seal grommets
- Thread sealant
- Sealing washers
External Sealing
Leakage at the transmission fluid pan gasket often can be stopped by tightening the transmission fluid pan-to-case bolts to specification. Refer to Torque Specifications. If necessary, install a new transmission fluid pan-to-case gasket only if gasket is damaged.
If leakage is found by the solenoid body connector, refer to Solenoid Body Assembly Service and Repair.
When transmission fluid is found to be leaking between the transmission case and the transmission fluid cooler tube case fitting, tighten the fitting to maximum specification. Refer to Torque Specifications.
NOTICE: Do not try to stop the transmission fluid leak by increasing the torque beyond specification. This can cause damage to the case threads and/or case fittings.
If the leak continues, install new transmission fluid cooler tube case fittings and tighten to specification. The same procedure should be followed for transmission fluid leaks between the Oil-To-Air (OTA) cooler and the OTA cooler tube fittings.
If leakage is found at the manual control lever shaft, install a new seal.
Check for transmission fluid leaking from the end of the extension housing. Leakage can result from a damaged seal, missing garter spring, worn extension bushing, damaged Output Shaft Speed (OSS) sensor O-ring or the output shaft retainer (vehicles equipped with a fixed yoke). Install a new seal assembly as necessary.
Inspect the line pressure plug for leakage. Make sure it is tightened to specification. Refer to Torque Specifications. If tightening the line pressure plug does not stop the leak, the case threads and/or line pressure plug could be damaged. Remove the line pressure plug and inspect the line pressure plug and case thread for damage. Repair as necessary.
Transmission Fluid Leakage in Torque Converter Area
In diagnosing and correcting transmission fluid leaks in the pump assembly and torque converter area, use the following procedures to locate the exact cause of the leakage. Leakage at the front of the transmission, as evidenced by transmission 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 transmission from the vehicle. The paths which the transmission fluid takes to reach the bottom of the torque converter housing are shown in the illustration. The following 5 steps 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.
2. Transmission fluid leakage by the outside diameter of the pump seal and pump body will follow the same path as leaks by the inside diameter.
3. Transmission fluid leakage from the 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.
4. Transmission fluid that leaks by a pump to case bolt 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.
5. NOTE: White facial tissue will aid in determining the color (transmission fluid is red) and source of the leaking transmission fluid.
Engine oil leaks are sometimes incorrectly diagnosed as transmission pump gasket leaks. The following areas of possible leakage should also be checked to determine if engine oil leakage is causing the concern.
- 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.
- 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.
- Leakage at the crankshaft rear oil seal will work back to the flexplate, and then into the torque converter housing.
Leak Check Test with a Black Light
NOTE: Dye-Lite(R) ATF/Power Steering Fluid Leak Detection Dye 164-R3701 is used to detect a transmission fluid leak.
1. Add dye to the transmission fluid. Use 30.0 ml (1 oz) of dye solution for every 3.8L (4 qt) of transmission fluid.
2. Using the 100W/12 Volt DC UV Lamp, start and run the engine until the transaxle/transmission 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 DRIVE and REVERSE ranges to increase pressure within the transmission. 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 transmission fluid leakage is evident and the probable source of leakage can be determined.
External Transmission Fluid Leaks
