Im driving on the highway for about 20min with no problems but once i get to the bumpy parts and acclerate a bit it will just pop out. I will put it back in and 2min later it will pop back out, i put it back and and it stayed in for about 30min before i took the ramp off. The shifter is weird it will stay between 5th and reverse instead of going to neutral. It kinda pulls away from fifth gear, It very tight not loose it should go back into neutral with ease. I drove to 1hour on the freeway last time and it never gave me this problem. Yet before that time it did it over a bumpy road. What could this be?

 

try checking out the syncros, in the transmission, also check out the transmission cables

 

How does the trans shift in any other gears? Sounds like 5th gear syncro is going.

 

If its popping out of gear its time for a new transmission.