You don't need it.

I will add that I went South last month from NY to Florida towing our 5th wheel with my 2017 Ram 3500 with the 6.4 Hemi. I worried some about going down Fancy Gap On I-77 entering North Carolina from Virginia (a vertical descent of 1,289 ft. over 6.2 miles. There's three runaway truck ramps. The first part of the grade is moderately steep but becomes more aggressive about halfway down). With Tow/Haul engaged, I downshifted manually to 4th gear and road down the hill at 55mph and never touched the breaks once. I was relieved when at the bottom but also impressed with the Ram's performance.