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: Exploded View Of Automatic Transmission System External Sealing - 4R100

Courtesy of FORD MOTOR CO.

Fig 2: Identifying Automatic Transmission System External Sealing Item Description Chart

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 . 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 CHECK .

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 cooler lines. 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 .

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 344.75 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 and tighten a new drain plug to specification. Refer to TORQUE SPECIFICATIONS .

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 . 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.