I had towed my Open Range 337RLS for over 6 years with a 2005 Dodge 2500 4x4 with the 5.7 Hemi and 3.73 gears with no trouble. It took me where ever we wanted to go. Probably towed close to 40000 miles. The Dodge was getting some mileage on it and I had the chance to get a great deal on a used '14 Chevy crew cab with the 6.0 and 4.10 gears so I traded. Every now and again I see the Dodge around still going strong.
I know this does not say anything for the 6.4 but if I could do it with the 5.7 the 6.4 should be even better. I had looked at the Dodge with the 6.4 but couldn't get a great deal. Good Luck and Happy Camping.
