I've been using my F-350 7.3L diesel automatic 96,000 miles for a daily driver and for pulling various trailers (mostly horse trailers) since I bought it in June 2001. I've been quite pleased. I check the tranny fluid for discoloration and change PROMPTLY to avoid auto tranny damage. The only problem I've had in the four and half years is an o-ring on the oil line going to the oil cooler came apart (losing quite a bit of engine oil and scaring me half to death) at about 40,000 miles. The dealership that fixed the o-ring implied the low oil pressure switch would have shut the truck down before any permanent damage (hopefully) if I hadn't seen the puddle and shut the truck down on my own.