hmmmm....long shot, but loose spring on clutch disk maybe? happened to me. spring fell out of my clutch disk, and was jammed on the flywheel bolt. hmmm....also see if you can pull up and down on the shift lever(on the tansmission, where the cable attaches). i installed my tranny once in the dark, and knocked one of the clips off of the tob. same problem your having. if you can pull up or push down on that lever, your tob clip came off. other than that, make sure your cable is adjusted.