Im working a Rd 5200s freezer app truck.. when preforming a Pm noticed when moving multi task handel to high speed lift noticed a loud knocking noise as the carriage moves up the the 3rd stage and the second stage seem to move up 2 to 3 inches when releasing the handel to center position the 3rd and second go back down it only does this with high speed lift.. im thinking its the lift chains having way to much strech.. truck has 8441 hours lift chains were replaced at 3000 hrs