Car slipping out of 5th and 6th gear after replacing pivot shaft bearing, breather, and seal

I just replaced the shifter assembly (bearing, seal, and breather) all pre assembled off ebay. I've taken the assembly in and out of the car like 8 times and verified that I'm putting everything back together correctly. From what I can tell it's not linkage, everything's put in correctly, shifter assembly is put together correctly (it only goes one way) and for whatever reason the car just won't stay in 5th and 6th gear. I also replaced the trans fluid while I was at it with redline 75W-80 and I didn't overfill or underfill either. I can hold the shifter in gear but obviously that's not good for the trans.

At this point I feel like the bearing must be faulty but I can't imagine that's it because I feel like other gears would have issues too. Does anyone have any ideas or suggestions? Yes the car was in neutral when removing and inserting the shifter. Maybe it really is the linkage and I somehow screwed something up?

 

Check this out. It might help just to make sure you didn't miss anything.
https://mazdaspeeds.org/index.php?t...haft-seal-bearing-breather-replacement.10062/

 

I looked at that a few times but I never noticed the little pin has a little taper, I’ll have to check that out.

 

Triple checked everything, ran the car in 6th gear without shift linkage and it still popped out, at this point it's narrowed down to either faulty parts or 5th and 6th gear decided to leave the chat while the car was on jackstands. I've got a replacement assembly coming in tomorrow so we'll see.

 

Looks like it's the synchros. Not really sure how that happened.