My 2014 8 ft CO Alaskan rides in a 2008 GMC 2500 Duramax diesel and it handles it well. Allison transmission is great. I get 19- 20 mpg at 70 mph on the flats. I just came back from a three week trip to wyoming and got an average of 18 mpg. I love my GMC diesel. I could use air bags but it still handles it well with Timbrens and Bilsteins. Good luck in your search.