So I have been up and down Davis Dam a few times both directions, Wolf Creek South bound, Cabbage Patch both directions, North Cascades Pass, Stevens Pass, Outlook, Siskiyous and many other West Coast hills and mountains with my old 2001.5 towing at 20,500 combined. RAM/Dodge did not build this old truck to be real safe doing these mountains at these weights, so I had to do it myself with custom tranny, smart controller, and exhaust brake. Along the way I upped it to 325/650-700 at the rear wheels. So it ran up this hills, mountains, and passes just fine.
Fast forward to this fall and we bought a new 2015 3500 4x4 CC SB with Aisin optional tranny. This new truck does it all, quietly and smoothly without any mods. The 5th wheel hitch locks into OEM frame mounted pucks, the brake controller is built in, and the exhaust brake works seamlessly with the tranny/engine with two modes available.
Did J2807 standards have anything to do with this? Who cares, they RAM and the others most likely got it right in recent years.
We all win!
Chris