Ranger tranny puking

A friend of mine has had his Ranger for 2 1/2 yrs. He leased it new & has had numerous problems from the start. I don't know what engine or tranny are in it. It's an Edge, if that helps. There are only 14k miles on it. Last weekend he was towing his boat home & when he got there he found tranny fluid all over his boat & trailer. Combined weight for both is about 3500 lbs. The truck has a factory tow pkg. At first the dealer tried to blame it on the tranny being over-filled but they were the last to put fluids in it. Now they're saying that he needs a larger cooler ( at his expense) & if he doesn't, he has to eat replacing it if it blows. I know the route he takes with this boat. There are no hard pulls & he never beats the truck or tows in OD. Anyone have any idea what the problem might be? I think it's about to blow & the dealer just doesn't want to have to do another major fix for free if it does.

Thanks!

i would get an attorney or at least the BBB INVOLVED IN THIS ONE. he could also call ford warenty himself and explain his situiation. that vehicle is rated to tow 4,000lbs