I can tell you since 2015 RAM has been very trouble free.
I tow 34-35k combined West Coast. Truck handles the load great in all weather conditions. I carry a 6k pin with my factory rear air ride. Truck sets exactly the same loaded or unloaded. The ride is much better than a regular sprung truck while maintaining a nice lower entry height.
The AISIN trans is rock solid. And are used in many other Medium duty applications along with the Medium duty CUMMINS engine.
LongHorn 3500 DRW Crew Cab, AISIN, 4.10’s with factory Rear Air. You will thank me.