Good cases to be made for all manufacturers and models. We had dually diesel, went to Ford 6.2 gasser. Of course our campers have weighed in at 3,600 pounds, not 4,500, but we have been all over out West and never had an issue. In the real elevations we lock out 5th and 6th overdrives and occasionally run in 3rd, may have shifted down into 2nd a time or two very briefly. Still all and all we would not switch back to diesel. it's just a choice, no right or wrong. We also own a fifth wheel and have had no issue with that either. :) Again whatever floats your boat.