I run 580-600 miles a night across the Appalachian mountains in a 13 Volvo auto this is the best truck I've driven here other than the 02 and 03 models (I loved those trucks) I've got 264,000 on it and so far the only problems it has had are the vec sensor had to be replaced and the soot sensor on the regen system went bad . This truck runs the same whether you've got 4000 or 40,000 lbs on it and still gets 7-7.5 mpg the engine brake and transmission are awesome in the mountains I think these are the safest trucks the company has bought in a long time