Forgive my ignorance but you have the clutch assembly then the belt is attached to it what is the other side called that that belt runs to? Mine has about an 1/8th in play in it. I can slide it in in out on the shaft. I tried to tighten the nut and it seems tight. I put enough pressure on it to start turning the track and the entire sled started to move. Is this movement in and out on the shaft normal?