I have a small leak in the C6 tranny on my 74 F-100. I'm having a hard time pinpointing it. I was going to get the tranny serviced this spring anyway since I hadn't gotten to it after I had a whole bunch of other work done last year. The fluid was good and the tranny shifts great. It leaves about a 2-3 inch spot after sitting for a week or so. I'm hoping its just the pan but I can't see where its from and it appears it is more towards the front of the tranny and not the back. I know if it ends up being the one for the torque converter the tranny has to come out. Can the seal for the shifter be done with the tranny in the truck or does the whole thing have to come out with that one too? Tomorrow I am going to get under the truck again and clean off as much as I can with a flashlight to see if I can spot the problem, hoping its just the pan.

 

A lever seal can be replaced in the vehicle. Check the filler tube "O" ring and tube itself.
They can crack in the "O" ring groove.
Also the servo and modulator.

Or the pan gasket may be leaking.


Sitting a few days will allow the convertor to drain back into the pan raising fluid level above the lever seals.