I just bought a 2015 Ford F-250 SD 4X4. My old truck was a 2005 Ford F-250 SD 4X2. I'm using the same Reese 15K hitch in the new truck as I used in the old truck. I measured the height of the bed of the box on the 4X4 and it sits about 5" higher then the bed on my 2005. My new truck has 20" rims, my old truck has 18" rims.
Last weekend I drove over to our RV storage yard and hooked up the trailer to the new truck and measured the height of at the front of the trailer with the height at the rear of the trailer with the landing gear retracted. There is a 4" elevation difference between the front and rear of the trailer, with the front sitting higher than the rear. I then lowered the yolk of the hitch down one bolt hole.
It changed the trailer elevation about 1.5." So now I have a 2.5" difference between the front and rear of the trailer. My question to the group is this close enough, or do I now need to look at adjusting the pin box height?