Who's towing what with the new 6.6 gas from GM. How does it do in mountains, how much weight are you pulling, what kind of mileage towing and empty. You all have the real answers, I thank you for you...
Can get 9mpg towing a 6klb high profile boat (has a tower with a bunch of speakers and stuff on it) at 75mph with a new 5.3 10 speed. Which is 1mpg more than same boat 5.3 6 speed. For comparison.