Just something to think about...
I know a guy who has a 2002 8.1 with the allison. He babies it. Anyway, the truck has less than 8k on it and has problems with the tranny. The thing is, nobody knows how to work on them and information isn't readily available. Its been to the dealer three times now. Its also on the second tranny, and still has problems.
As for the 8.1, he said that it continuously burns oil. Two and a half quarts every 2000 miles. I talked to a friend of mine who knows a service manager at the same dealer. The service manager showed him a tech sheet from GM, stating that the motors are supposed to burn that much oil.
I'm not anti GM. In fact just the opposite. If it were my money, I'd take a 2500 HD crew cab with the Duramax. I rode in one in November. It was like a Cadillac. Moved pretty good too.:angel: