just finished a 2588 mile trip pulling about 12000 lbs. (5th wheel)DW kept track and here is the low 9.4 and high 11.9-2013 Dodge 3500 4x4 with 6 speed stick-truck did a very good job-I was impressed!...
My 2001 Dodge diesel dually got about 8 mpg going into about a 30 mph headwind going to New Mexico and about 9.5 mpg coming back home. Running 65-67 mph both ways pulling our 15,000 lb. Fuzion toyhauler.