A little off the wall and away from Ford Harleys, but I have a little engine problem. I'm the chief of a rescue squad that has 3 Ford E350 ambulances, running the 7.3 liter engine. One of the trucks, with 89,000 miles on it, has blown a rear oil seal. From my experience with gas engines, it usually takes some excesive oil pressure to do this, which you would see from the dipstick or PVC system first, or an overfill. Not sure here. Couple of questions....

1. Why did it go?
2. How much to fix?
3. Does it involve an engine teardown, or dropping the engine/transmission from the bottom to repair.

Appreciate any insight into this. Dealer can't say why it would go, it sorta surprised them, too. I also posted up on the Engine Forum......Thanks