T90 Synchro Key

I have a 59 Cj with a T90. This jeep had been gone through from top to bottom by a previous do-it-yourselfer, and although they used a whole bunch of new parts and were very thorough... sometimes they missed the mark. The trans worked good when I got it, other than the occasional pop out of second gear, but soon the synchro went out and shortly after that 3rd gear synchro stopped working too. I pulled the trans apart and found many new parts and some formerly rusty gears that seemed to be working fine. At issue, the 2nd gear blocking ring was hammered onto the gear cone and the strut keys had bypassed the blocking ring slots chewing off the end (and likely what hammered the blocking ring to the cone?).

I now know that the clutch hub could be put in backwards- I tested this because having never seen this before I did not pay attention to it's direction upon disassembly so I don't know if it was correct . Installed backwards the keys are moved far away from the blocking ring and could cause this. However, once I reassemble everything correctly and brace up the trans mission shafts into the installed position the depth of the keys is only slightly better. When I move the gears away from each other the keys are barely engaged into the second gear ring and it looks like this could easily happen again. I considered shimming the rear shaft forward but the slightest increase over factory jams the blocking rings. I called Novak and a really nice guy measured the keys they sell but they are the same length. Does anyone know if there are different synchro keys that will work... or something else? Do I just heat the ends carefully and move them out a bit??

 

When I rebuilt my t-90 there were some longer silver keys that didn't work for me. Omix-ada parts had a terrible matchup against the original parts. The mainshaft was long in the sliding gear area.
In your case a new blocking ring and keys ar certainly needed and check the springs that snap under the keys. Without the original parts to reference it will be hard to tell what part is out of spec.

 

Welcome from Ga.