Re-gearing is not needed with the 6-speed.
I would check into wether your transmission cooler is the same size as with the tow package, and if you need to add an engine oil cooler.
Bewared that there is an open TSB for the transmission programming. The torque converter clutch slips at heavy throttle when operated at max GCWR, so the programming leaves the torque converter unlocked more. This saves the clutch, but at the expense of more heat. This was causing overheating issues for the motorhome guys, but Hayden came out with a better fan clutch that kicks on sooner.
