i find the only time i need to work on mine is when i need to add oil to the hoist. since filling it up once i havent had to get under the bed. i use a 6" x 8" x 6' oak beam and prop it under the box where on mine is a channel that just so happened to be there it locks the top in place. the other end rests up against the front of the rear tires. when i lower the box the beam locks itself in place. i have one for each side but due to their strength i only need one. in the the 7 years i have the truck ive only used them twice. once was to put oil in the hoist and the other time to paint every thing under the box and frame. go to any big construction site they always have big lumber to get rid of that big equipment was shipped on. its new and strong and free. laalaa