My 72 tooth metal spur gear got loose, so the slipper was slipping. I tried to tighten it and the shaft would just free spin. I went to my LHS and bought a plastic one. managed to tighten it made about 4 runs and it got eaten by the clutch bell. tried to put the metal one back it but the 12 little pegs wont fit in the metal one. can I throw it back on w/o them or should I try and get a plastic one again? Is there a trick to get the spur to tighten all the way? every time I try the shaft just free spins am I doing something wrong?