Lincoln Corsair: Automatic Transmission - 8-Speed Automatic Transmission – 8F35/8F40 / Diagnosis and Testing - Leakage Inspection

Leak Check Test

1. With the vehicle in NEUTRAL, position it on a hoist.
   REFER to: Jacking and Lifting - Overview (100-02 Jacking and Lifting, Description and Operation).

1. Inspect the gasket and sealing areas for evidence of leakage.
   

1. Trace the transmission fluid leak to the highest point.
   

1. Clean the area of the suspected leak.
   

1. Lower the vehicle.
   

1. Remove the transmission fluid fill plug.
   

1. Add leak detection dye to the transmission fluid. Use 1 fl oz (30 ml) of dye solution for every 4 qt (3.8 L) of transmission fluid.
   

1. Road test the vehicle for at least 1 mile with at least 1 application of the TCC .
   

1. With the vehicle in NEUTRAL, position it on a hoist.
   REFER to: Jacking and Lifting - Overview (100-02 Jacking and Lifting, Description and Operation).

1. If the source of the leak is obvious, repair as required.
   

1. After the repair, clean the affected area.
   

Leakage From Torque Converter Housing

1. Leaks from the torque converter housing can originate from several locations. There is a drain hole at the bottom of the transmission case (torque converter housing) that allows transmission fluid to exit the transmission case. See illustration. The following locations correspond with the possible causes of fluid leaks.
   
   1. Drain hole
      
   1. Torque converter weld, outside edge
      
   1. Stud welds
      
   1. Torque converter seal
      
   1. Torque coverter pilot hub weld
      

1. Remove the torque converter.
   

1. Using a black light, observe the torque converter housing. Inspect for evidence of dye from the pump bolts, pump seal, and torque converter hub seal. Repair as required.
   

1. If the source of the leak is not evident, continue with this procedure to leak test the torque converter.
   

1. Place the torque converter in an arbor press. Support the torque converter on the mounting pads.
   

1. Install the torque converter leak tester (307-421) into the torque converter hub.
   

1. Secure the press. Apply enough force from the press to seal the torque converter leak tester (307-421) into the torque converter hub.
   

1. Connect a compressed air supply to the torque converter leak tester (307-421).
   

1. Apply air pressure to the valve and inspect for leaks at the torque converter hub welds and seams. Use a soap bubble solution around those areas to aid in diagnosis. If any leaks are present, install a new torque converter.
   

1. Inspect for leaks at the stud or mounting pad and balance weight welds. Use a soap bubble solution around those areas to aid in diagnosis. If any leaks are present, install a new torque converter.
   

1. After leaks are repaired, clean the remaining transmission fluid dye from serviced areas.