[OLDIRON69]

My '05 2500HD gets 8 at best towing a 24' enclosed trailer. If I drive right..which hardly ever happens I get 15 on the hwy empty. I'm a tree broker and haul alot of heavy loads. I really need the D-max but the 6.0 gets it done. Water pump just replaced two weeks ago, believe it or not it was putting so much drag on the motor for the last 2000 miles it had the power steering pump sounding like a cat in a vise..I think the mileage is even improved 1-3..still keeping an eye on fuel to see but I know it was killing the mileage even more.