Ram 2500 Towing Help!

We towed a 10,400 lb actual weighed weight high profile 5th wheel with our '05 2500HD auto/3.73 Hemi powered Ram all over the south east. It did a fine job for the 120k miles I owned it and ran like a new truck when I traded. The faux 5spd 545RFE trans was an oddball but it never gave us any trouble. It would run in O/D on the flats no wind, Direct 2700rpm with any headwind or incline and 2nd at 4200rpm 60mph on any uphill. I was very happy with the performance of the engine. Others cringe and give themselves a headache at the sound of an engine running in it's normal power band. I like the hot rod sound of a V8 at 4k~rpm. We averaged 8.5~mpg towing 65-68mph. For comparison, my '03 duplicate Cummins powered Ram towing the same 5th wheel averaged 10.5mpg.