I am about to purchase a 2016 RAM 3500, Longhorn, 6.7L diesel, long bed, crew cab. This truck has an AISIN Transmission with a 3.42 rear end. I will be towing a 13,500 lb 5th wheel for 40% of the miles. The other 60% will be light loads in the truck bed. Technically I do not need the AISIN to...