The Fifth Airborne Hitch we have has a line on the drivers side of the box "fill to this line" or something like that. I installed the pin box myself and adjusted the physical height of the pin to the height of the old pin. As the fiver was level with the old pin box so why mess with the ride height if fiver is riding level, if not adjust up or down to level to the desired height. I hope this helps. I can adjust air pressure to the air bag from cab of truck and will adjust air pressure if roads sections are very rough then readjust to correct pressure when roads smooth out.