I had an '01 when they 1st came out in the crew cab, truck was great. The milage (10) is why I sold it for duramax. In a truck the 8.1 only come with an allison. They cost 4 to 5 grand to rebuild. They are only good up to 375 rwhp stock after that they will slip and burn the cluchtes up. I spent about $2500.00 on the allison in my 07, when it was new to hold the extra power form EFI Live out of the duramax.