I have a 2012 3500 4x4 CC with the max tow package. That is it has a 4:10 rear end. I just turned 10,000 miles. Yesterday I took a road trip to Lake Placid, Fla. and according to the computer I was getting high 16's to low 17's That is running between 55 and 62 mph with the cruise on. The first ride was when I bought the truck in NC and brought it home to SW Fla. a little over 700 miles. I ran an average of 75 on the interstate and got at 13.5 mpg. I tow a 36 ft. Cedar Creek and I don't have an accurage weight on it but I have been averaging 9.5 to 10 mpg with the cruise, tow haul mode and exhaust brake engaged and running about 65mph. By comparison my previous truck a 3/4 ton Ram 5.9 CTD auto and 3:73 averaged about 10 mpg with the same trailer. I suspect as I put more miles on the truck the mpg will improve. It did with my previous truck. The only motor in the 2012 3500 was the CTD. You can get a hemi in the 2013 however.