Did my first long trip yesterday pulling 5th wheel trailer, about 15,000 lbs. Truck did great, acted like it wasn't even back there. My question is those of you with 6 sp manuals, what rpm are you using for your shift up? Had some trouble shifting in 1st and 2nd, once I got to 3rd she was smooth as butter. I know, from articles in TDR, not to lug under 1600 and should keep the rpms in the 1600 to 2200 range.