O. K, I have a 2011 DRW 3500 w/3. 73's and auto trans. I tow a 14,000 fifth wheel and Have towed over 8,000 miles this year. It does fine in the flat country and some small hills. i have found that it pulls like a frieght train running 70 mph in 6th gear but I really dont care to run that fast. i would rather run 60-65 but find the truck seems to struggle more at those speeds. i usaully shift to 5th at 60 or below. The larger mountains out west are a whole nother story. I have posted this same topic on here and got varying opinions. So I have come to the conclusion that I either need to go to 4:10's or throw my warrenty out the window and do a full delete/programmer. IMO I think the 4:10's with this 6 speed auto would be the best setup for larger trailer weights,This is My Opinion though I have not pulled with this combo. Thanks Steve
With the 3. 73s if you do a delete and programmer you will smoke 5th & 6th gear real easy.