When I bought my 06 QC 4x4 with auto, I had a 7000 lb tow behind. We found a killer deal on a 5th wheel on a trip to the East coast and bought it. I was going to put an aux tank in the bed of the truck but decided to weigh it first with the trailer..... The truck with the 5th wheel attached weighed 9850 lbs, the total rig weight was 18580. People have been telling me not to worry about exceeding the gvw. . any thoughts appreciated. . PS I do have a Jake brake and love it.