My truck is a 2014, and I have the 4.30 rear end, but mine has no problem pulling our 12,600 pound dry fifth wheel.
Yes it drops down into 3 or 4th for big hills, but having owned diesels before, I knew that was one drawback of the gas engine.
12,000 miles and no issues at all.
Last edited by pre6422hornet; 09/08/15.