Leakage Inspection

Leakage Inspection

This transmission has the following parts to prevent external fluid leakage:
^ gaskets
^ lip-type seals
^ O-ring seals
^ seal rings
^ seal grommets
^ thread sealant
^ cooler bypass valve (CBV) sealing washers





External Sealing

Leakage at the transmission pan-to-case gasket can often be stopped by tightening the retaining bolts to specification. 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-Accumulator Body, Solenoid Body.

Check the transmission sealing washers on the cooler bypass valve (CBV), fluid filler tube connection at the transmission case. If leakage is found, install a new short fluid inlet tube.

Check the transmission sealing washers on the cooler bypass valve (CBV), fluid lines and fittings between the transmission and the fluid inlet short tube in the radiator tank for looseness, wear or damage. If leakage cannot be stopped by tightening a fluid line tube nut, install new parts. When fluid is found to be leaking between the case and the cooler line fitting, tighten the fitting to maximum specification.

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 a new cooler line fitting and/or sealing washers on cooler bypass valve and tighten to specification. The same procedure should be followed for fluid leaks between the radiator cooler and cooler line fittings.

Check the engine coolant in the radiator. If transmission fluid is present in the coolant, the transmission fluid cooler in the radiator is leaking.

The transmission fluid cooler can be further checked for leaks by disconnecting the lines from the cooler fittings and applying no more than 345 kPa (50 psi) air pressure to the fittings. Remove the radiator cap to relieve the pressure buildup at the exterior of the fluid cooler tank. If the transmission fluid cooler is leaking, will not hold pressure, or both, install a new transmission fluid cooler in the radiator.

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

When a converter drain plug leaks, remove the drain plug. Install a new drain plug and tighten to specification.

Check for fluid leaking from the end of the extension housing. Leakage can result from a damaged seal, missing garter spring or worn extension bushing, or damaged speed sensor plug. Install a new seal assembly, bushing, or both, as necessary.

Inspect the line pressure plug for leakage. Make sure it is tightened to specification. 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.

Check for leakage on or around the cooler bypass valve (CBV). Repair as required.

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 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 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 five steps following 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 that leaks by the inside diameter of the front pump seal follow.
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 (red is transmission fluid) 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.
^ 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.
^ Leakage at oil pressure sensor.

Leak Check Test
Determine the cause of the leakage before repair.
1. Remove the fluid level indicator and note the color of the fluid. Original factory fill fluid is dyed red to aid in determining if leakage is from the engine or transmission. The red color should assist in pinpointing the leak.
2. Remove the torque converter housing cover. Clean off any fluid from the top and bottom of the torque converter housing, front of the case, and rear face of the engine and oil pan. Clean the torque converter area by washing with a suitable non-flammable solvent, and blow dry with compressed air.
3. Wash out the torque converter housing, the front of the flexplate and the converter drain plug. The torque converter housing may be washed out using clean solvent and a squirt-type oil can. Blow-dry all washed areas with compressed air.
4. Start and run the engine until the transmission 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 Overdrive 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), and inside the torque converter housing and front of the case. Run the engine until fluid leakage is evident and the probable source of leakage can be determined.

Leak Check Test with Black Light
Oil soluble amine 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.