I own a 2002 Chevy Duramax 4x4 ext cab 60,000 miles on her and was thinking of trying a new Ford with the 6 liter diesel engine.It is a 4 door 4x4 short box, auto. 3.73, 2500 and was wondering what kind of mileage the Fords are getting towing and empty. I am only thinking about doing this...