For the people that have latter year Rams you might want to do what I did to mine. I have a 2017 Ram Mega DRW and I had the 3 spacers removed between the springs and the axle perch. The rear tailgate of my Ram was 59" previously and now it is 57". When I took out the 3 spacers I just placed them back on the top of the spring pack so I could use the same u bolts and it also keep the spacers with the truck.
Years back I had a F550 4X4 built for me and it had a dually pickup box on it and I had them do the same thing to it but instead of spacers it was a couple of lower springs then placed them on top of the spring pack so I could hitch the 5er to it. Then a few years latter I went back to a truck camper so I had the springs put back to normal. Worked great.
Take a look under you Ram and see if you don't see the spacers there. I also had my alignment checked as everybody thought it would change my camber. Didn't change anything as castor and camber was still on. Truck sits just a little up in the rear now. I'll see how it all works when my new 5ers gets here next week (hopefully). 5er should be born today 9/28/2017 and at the dealer next week for some dealer installed options.