Leakage Inspection: Notes

The 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

Fig 1: Identifying External Sealing - 4R100

Courtesy of FORD MOTOR CO.

Leakage at the transmission pan-to-case gasket often can be stopped by tightening the retaining bolts to specification. Refer to TORQUE SPECIFICATIONS in this article. 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 in this article.

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. Refer to TRANSAXLE/TRANSMISSION COOLING .

If vehicle is equipped with power take-off, check the sealing gasket at the power take-off 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 or sealing washers on cooler bypass valve and tighten to specification. The same procedure should be followed for fluid leaks between the oil-to-air cooler and 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 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. Refer to TORQUE SPECIFICATIONS in this article. 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.