I have had an intermittent transmission leak for a while now...it only leaked if truck sat on an incline (uphill) and was not driven for 2 days. On the second day it would dump a cup or two of transmission fluid down the driveway. I am posting the resolution and what it was for anyone else trying to pin point a trans leak.
70,000 miles, 2009 Expedition El 4wd/AWD. There is a "bulkhead" connector on the passenger side of the rear part of the transmission. On the second day after all ambient heat of driving had dissipated, while on an incline, the seal around the wire bundle entering the transmission would leak continuously. In order to repair....it requires dropping the pan, disconnecting the wires internally, removing the bulkhead connector and replacing the seal, oh and $450. They couldn't find the leak initially and had to put dye in it but several days later it was found. I am only posting this because you guys have been so helpful to me in other forums over the years I wanted to try and shorten y'alls troubleshooting in the future with the small piece of info I just paid for at the dealership.