Hey Everyone. I've been having this issue for several months know where I would pop out of 4th gear under load. I tried several things from changing the under hood bushings and even switching to a short shifter cage. Has anyone experienced this before? I'm hoping it isn't synchros.

 

Popping out of gear is indicative that there is an internal issue with the trans. Either the synchro, the shift fork, or the detent. Time to pull it apart.