I tow an 11K 5th wheel with a 6.4 Hemi, 3.73 gears. It does okay but the tranny SUCKS. Gear spacing and shifting behaviors are atrocious. The shifting can be fixed by doing it manually which is not a big deal but the gear ratios are what they are. Mainly, the 1-2 gap is too great and it really sucks towing heavy. Daily driving and towing light it isn't a problem but when hauling heavy you just get stuck in this Bermuda triangle where you can't hold 2nd but are at the top of 1st. This mainly comes up on hills and I'm out west with lots of them. If you're looking at one of the new ones with an 8spd I imagine all this will be gone and it will be an absolute beast.