Just a thought....really long magnesium chaincase...steel chain... think coefficient of expansion difference between the two metals. If the chain is tight when the case is cold, it is going to get REALLY tight as the chaincase warms up and the shaft centers move away from each other. Think of the forces that are in play here. If I owned one of these sleds I would make sure that the chain had a little slack immediately after I had made a LONG full throttle pull in deep powder. Again just a thought...feel badly for you guys that are having this issue.