I currently have a 2015, 4x4 3.5 V-6 Eco-boost Lariat supercrew 5.5 ft. box with 78,000 miles. I have the 502A pkg. with 3.55 axle and trailer tow pkg., with tow haul and 145 in wheelbase, spray-in bed liner. I have pulled the above trailer for 12,000 miles over the past 6 years and it has...