My wife has a 07 automatic gt that all of a sudden started leaking. The car had been parked for about a week due to wintery weather until last night when she backed out of the driveway and noticed a fairly large stain. After checking it out I looked under the car and saw ATF covering the side of the tranny on the driverside. Once I jacked it up and got underneath I could tell it's coming from the top almost near where the header bolts to the cat. The car has never leaked a drop until this incident and only leaked a couple drops since parking in the garage last night. I'm not sure if the fact that I have a fairly steep driveway or the freezing weather has had anything to do with it. Any ideas?
Im thinking the seal between the engine and gearbox (packing) could be leaking, hence the puddle of ATF. It also wouldnt hurt to check if all the drain and refill nuts have been properly tightened. As you said you have a steep driveway and since the level of fluid is filled almost to the top of the nut it may not have been tightened properly and although it didnt drip earlier since it was kept at the angle for a extended duration of time fluid may have found a way out.
I had a similar problem but I would only leak a few drops at a time. I brought it to ford and got it checked out, they said it could be the torque converter or the pump. Turned out it was the seal on the torque converter