So my little brothers Z400 trany went out.... it wasnt while he was shifting or anything, he was wideopen going down the pipeline.. no bumps no nothing straight smooth 5th gear wide open WAM lockup.. mottor still runs, just doesnt move. So we pull the motor out, clutch is fine, take apart as fara s you can go w/o splitting the case yet and hmmm theres a tooth and peice of a snap ring... any ideas on how this happened?