A couple of years ago I bought a reverse chaincase off of E-bay for my sled. I had a local guy put it on and it appeared to work in that it would spin the track in reverse on a stand. Since it was installed in the summer I did not get to test it until the next season. When I would try to use it, it would not move the sled and would grind as if the gear was not engaging. I took it back to the guy and we took it apart and reassembled it a couple of times to no avail. We took it apart again and realized the chain had been rubbing the guide and had ruined the chain. We replaced the chain and one of the gears, as well as the pins in the arm the moves the gear. It worked. The first time I tried to unload my sled off of my trailer it moved a littel and then the sled hung up on the edge of my ramp. It now does the same thing as before and grinds but does not move the sled when I try to use it. An adjustment? how tight should the chain itself be?