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 pan-to-case gasket often can be stopped by tightening the retaining bolts to specification. Refer to Torque Specifications. If necessary, install a new pan-to-case gasket only if gasket is damaged.

If leakage is found by the solenoid body connector, refer to Main Control Valve Body.

When fluid is found to be leaking between the case and the cooler line fitting, tighten the fitting to maximum specification.

If the vehicle is equipped with Power Take-Off (PTO), check the sealing gasket at the PTO unit for leaks.

CAUTION: Do not try to stop the 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 cooler line fitting and tighten to specification. The same procedure should be followed for fluid leaks between the oil-to-air cooler transmission remote filter, and the cooler line fittings.

If leakage is found at the manual control lever shaft, install a new seal.

Check for fluid leaking from the end of the extension housing. Leakage can result from a damaged seal, missing garter spring, worn extension bushing, damaged speed sensor plug, or the output shaft retainer (vehicles equipped with a fixed yoke). Install a new seal assembly, bushing, or both, as necessary.

Inspect the line pressure plug for leakage. Make sure it is tightened to specification. Refer to Torque Specifications. If tightening the plug does not stop the leak, the case threads and/or plug could be damaged. Remove the plug and inspect the plug and case thread for damage. Repair as necessary.





Fluid Leakage in Torque Converter Area

In diagnosing and correcting fluid leaks in the front 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 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 fluid takes to reach the bottom of the torque converter housing are shown in the illustration. The following five steps correspond with the numbers in the illustration.

1. Fluid leaking by the front 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, 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. Fluid leakage by the outside diameter of the front pump seal and front pump body will follow the same path as leaks by the inside diameter.
3. 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. Fluid leaks from the torque converter will leave a ring of fluid around the inside of the torque converter housing.
4. Fluid that leaks by a front pump to case bolt or pump gasket will be deposited on the inside of the torque converter housing only. Fluid will not be deposited on the back of the torque converter.

5. NOTE: White facial tissue may aid in determining the color (transmission fluid is red) and source of the leaking 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.
1 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.
2 Leakage at the crankshaft rear oil seal will work back to the flexplate, and then into the torque converter housing.

Leak Check Test with Black Light
Oil soluble aniline or fluorescent dyes premixed at the rate of 2.5 ml (1/2 teaspoon) of dye powder to 0.24 L (0.5 pint) of automatic transmission fluid have proven helpful in locating the source of fluid leakage. Such dyes can be used to determine whether an engine fluid or transmission fluid leak is present, or if the fluid in the transmission fluid cooler hose leaks into the engine coolant system. An ultraviolet light must be used to detect the fluorescent dye solution.