I was rolling along the other day in my 87 chevy 12 v 5spd in 4th gear and all the sudden I realized I must have slipped into neutral so I reached to put it back in gear and I was still I 4TH GEAR I tried every other gear and no go does anybody have a general idea what this might be.

 

any odd noises?

if not, it could be a busted shift fork or forks...

seems if you had a broken shaft or sheared teeth, it'd be making noise

 

Absolutly no odd noises what so ever just as if it slipped into neutral. There was no bang or bust just quit pulling and the funny thing I was not even calling on it, just taking it easy for a change. Is shift fork very common?

 

no, and I'd be surprised if it somehow magicly broke while in gear

you SURE you didn't oil down the clutch really bad or something?