My '08 is a Dodge 2500 Cummins. I get about 17 on the highway, empty. That's holding it at no faster than 75. It has the 3.73 axles and a manual tranny. I'm told the autos will do slightly better.

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

It's not over when you lose. It's over when you quit.