I ordered a brand new 2008, 2500, manual 6 speed transmission, with the option of the (new at the time) 6.7 Cummins. Trading in my 2004 Hemi AWD 1/2 ton. At best the 1/2 ton would only get 15 mpg. When I towed my camper with the 1/2 ton the very best I got was 7 to 9 miles to the gallon. It...