I only get 10-12mpg towing and up to 17 unloaded with my 5.9 CTD but it has the 4.10 gears. It is the 235hp standard output. I dont expect it to get diesel mileage, that's not realistic. I would get a 6.4 with the 4.10 gears so it would tow the best. I work for Toyota here at the Tundra engine plant. The mpg for the hemi is not that different from the 5.7 Tundra engine. If my camper was lighter I would buy a Tundra cause they are good and that's where I get my pay check. I like the Ram and I think it fills my needs but just wanted to hear from you guys that have already tried towing with them. Thanks and keep sending your thoughts.