By any chance does anybody know what this could be? Gears 1 to 4 are o.k. but when I'm in 5th and trying to go to neutral or 6th it will not release, it gets stuck. Sometimes it will release but most of the time it will not. Then whenever I can go to six it will do the same thing and it gets stuck in the gear. The car will still accelereate and go but I just can't take it out of gear. I have to stop for a while and move it around until it releases the gear. So far this is what some people have told me it could be: clutch, oil level, some rubber thing that goes in the gear box, or an actual gear. I hope someone can help me with this. I just put in a cutout but know I have to fix this. Thanks, junior

 

Your 5/6 synchro is shot. There is (3) keys located within the synchro hub. They are held in place with a thin piece of spring steel (about the diameter of a paperclip) that goes 3/4 of the way around inside the synchro hub. Those keys allow the synchro itself to glide over the hub and allow you to engage/disengage gears. When the retaing wire looses it's tension or the keys become dislodged (or misplaced) or even fall out of place entirely, you get exactly what you are describing.
If you have any mechanical knowledge, it's a very easy straightfoward repair. You can a new 5/6 synchro from D & D performance for about $100-$150.
All you have to do is pull the trans out, stand it up right, pull the end case off, and start pulling the pieces of the main shaft until you reach the synchro. KEEP EVERYTHING IN ORDER!!!!! KEPP EVERYTHING VERY CLEAN!!!!!
Good luck.
If you need any other help, shoot me a pm.
I've done this many times on my tranny and other tranny's