Broken shift fork ?

[Outlaw1]

Sounds like something in the shift rails is busted. Usually when a fork breaks it's not possible to get it out of the gear that it was in when the finger of the fork broke. When the fork breaks, shifting into another gear will engage two gears and effectively lock the trans up. Your trans shouldn't have anything majorly broke though. If I had brought my air tools I would break it down for you. I just don't have anything to bust the 5th gear nut off with. Good luck.