Not that I plan on buying a new truck but I was "building" a 2500 Quad cab short bed with a Cummins on the Dodge web site and was surprised that it says it comes with a 10. 5" rear (11. 5" in not a choice) and there are two choices for 6-speed transmissions - one of which is "heavy duty" and the other which apparently is not. Is the axle correct, do they not come with 11. 5"? Is the non-HD 6-speed the new one and the "HD" one the NV5600? Or is this all a horrible mistake made by their web design team?