5th gear loose on shaft

I've had a pretty noticeable rattle from my (supposedly rebuilt) transmission since I bought it from a member here back in 2017. I've put about 24,000 miles on it since, but it's recently gotten a lot louder. I originally chalked this up to clutch rattle, but it's become clear that it is more.

After raising the driver's side of the vehicle and pulling the fifth gear cover, I can clearly see that the fifth gear selector fork is loose, the fifth gear synchro ring is very loose (moves ~1/8" in and out longitudinally on the shaft in addition to its normal partial rotation), and the big fifth gear itself also moves in and out on the shaft (again, I'm not referencing rotation).

I compared to another box I had in storage and found that all of these components are sandwiched together might tighter. I don't have enough experience to know which components are pressed on the input shaft, but it seems like one didn't get pressed on enough.

Can anyone make a recommendation as to which way to proceed?

Here's a video of the looseness.

After removing the collar, T60, and washer, I found that the locking ring is not flush with the input shaft. I tried heating with propane and driving it on further, but there was no discernible movement.

Link to image of the output shaft

I assume I need to somehow seat that locking ring more tightly, but some confirmation would be great.

There’s a transmission forum on vortex. You may have better luck, posting there.

-Todd

vwvortex is dead, 100x worse than this. good luck over there. Plenty here and there from old threads. here is one
https://forums.vwvortex.com/showthread.php?5172611-DIY-Splitting-the-O2J-transmission-case-for-repair-or-LSD-install
i am NOT a pro at transmissions but from the work i HAVE done in the past, i can tell you that this IS NOT normal and something is REALLY messed up. i suspect the shaft is worn and the fork is as well. the fact that there is side to side is the shaft and the up and down on the shaft is the fork issue.
What trans code? o2j?

02b. I was able to get some of the slack out by adjusting the fork, but the gear is still loose on the shaft.

It's quiet now, but not shifting well. Sometimes it shifts buttery smooth. Most of the time, though, it's hard to get into gear.

With the engine running, and the clutch pressed, it will roll down a very slight grade in neutral. Again, with the engine running, attempting to push into first gear will slow the car down as the synchro catches. Popping back into neutral will allow it to roll again.

I feel like there is a fairly obvious answer to this, but I'm struggling to wrap my head around it.

From the image, the selector gear seems seated all the way. Are you possibly missing the thrust washer that sits behind the larger 5th gear cog? I definitely do not have that play you show in your video. I've swapped out 5th gear in a few different 02b boxes and don't recall any play. The shaft as a whole doesn't move right?

Pull the hub and realign the synchronizer, someone put the wrong pokey bit in the wrong hole. The tabs aren't lining up. While you're in there, ensure the needle bearing is installed(might as well replace it).

Edit: To clarify, it's the tabs that slide into the hub. You can see it's the small tab that's lined up in the big hole.