Welcome!
My choice is the RAM Cummins AISIN combo with 4.10's. I have 55K on my 15 DRW LongHorn with ZERO issues. I tow 33-35K combined and is rock solid with no overheating towing in all weather and grade conditions.
The Factory Rear air ride is AWESOME! Truck sets nice and low in alt ride mode and stays at that same level with 6K pin.