[m22mike]

I have a 01 Silverado 8' box, 8.1L, Allison, 3.73 gear. Bought it new and at the time did not feel I would get the use out of the Duramax, I only have 20K on the truck now.
I pull a 24' box and the thing can run 75 with little effort. I love the Allison, awsome tranny.
I see around 10 mpg when I tow and the same just around town, I love jack rabbit starts from a traffic light ! Hard to keep your foot out of it.
I do not think Chevy offers that motor anymore ??
One small issue with the my 8.1, since new I have always had to top off the oil about every 1500 mi. or so.
Mike