I pull a fairly heavy fifth wheel RV at around 21,000 pounds. Looking at ordering a 2021 3500 Club Cab dually with the HO and Aisin. This comes standard in 3.73 rear axle. A friend is recommending a 4.10 axle as he is concerned that the Aisin trans might hunt a lot with that weight. My fifth wheel is well within the towing capacity of either ratio of anywhere from 33K to 35K. Would like to hear from owners of similar 2019 or 2020 3500 trucks that pull trailers in the low 20K as to how their transmissions perform. I currently am pulling with a 2003 HO Cummins with a 6 speed manual trans and 4.10 axle but I am exceeding the rated towing capacity of the truck so it is time for a new one. C