I anyone familar with the Robin hydraulic lift system (Robin is the name cast into the hydraulic pump, control valve and both lift cylinders)? My GMC 9430 pickup truck has 2 hyraulic rams instead of one. How would I install a lift lock without damage (twisting) the box when lowered onto the lock? I would like to be able to leave the box in the lifted position without danger of having lower itself when at car shows.
It appears that the dumpbox is original and not an added feature.

I will get some pictures of the hydraulics tomorrow and add them to this post.