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.

 

First I'd clean the complete transmission off so its nice and clean then spray paint with light color paint all suspect areas. drive it then reinspect for leaks. This way you will not be guessing .From what your saying it sounds like the front pump seal could be leaking .If it is and is only leaving a 2 or 3 inch spot I would not worry about it till it got worst.It don't take much oil or trans fliud to make a 2to3 inch spot on concrete .

 

My C6 in my 79 was doing the same thing. I would park to where the truck was higher in the front and there was no fluid spot on the floor in the morning lol finally got around to replacing the front pump seal and it was fixed.