Well I don't pull 12K with mine, but around 10K and have no issues. 7.5 mpg so far is the lowest that I have seen towing for my truck. Usually in Fl I get 8.5 on average towing my camper in the sig. I wish mine did have the 4.10 instead of the 3.73, but realistically not an issue for what I am doing with it. Empty I get 13.5 to 17mpgs depending where. Hwy 17.0mpg unloaded at 70 mph in Fl. Otherwise in town I have seen it 13.5 but mostly I get 14-15 mpg in Fl. The 6 speed will be a blessing verse the older 4 speed when towing. I lock out 6th and town in 5th in FL and hitting hills will drop into 4th around 3500rpm while keeping speed. In the mountains u could hit 3rd but at the lower mph. It will drop into 4th and keep. Very reliable, just a great proven all around drive train. If u have read any of my previous post, I am very happy with this truck, and yes I have pulled with diesel prior (Duramax and Cummins).
