Your clutch could be bad, the dogteeth on the collar gear? may be gone. I know there called dog teeth, dont know about the collar gear name. Syncros dont have much to do with keeping a gear in gear, so thats probably not it.

 

Thank you MechE for replying. Really, the clutch could be it? Why would the clutch cause this? What are the chances of it being this instead of the dogteeth on the collar gear? Thanks again for your replies.

 

On a 93 5 speed what would cause the trans to jump out of fifth gear while driving?