just purchased a new to me Chevrolet Duramax 6.6 with the Allison automatic, just driving it around town yesterday running some errands it shows average fuel mileage at 10.6, what do you think. I think it's still breaking in. It's a 2013 with 55900 on it I previously had a dodge cummins that got about 12 mpg up until about 75k then it began to go up to 19 around town and 12 to 13 pulling my 5er. Never had a Duramax before.
