There's a tiny round nylon donut that snaps to the bottom of the pivot on the 4MT. That's certainly turned to powder. IDK if you can still buy them from Subaru or not. Might be able to 3D print one.....
The entire 4MT linkage was terrible and the design went away with the 5MT and besides the extra gear, lighter weight, greater strength, and lower low range of the 5MT, the significantly improved linkage is probably 50% of why I always did the swap. Just did one for a customer last week. He tracked down all the parts and brought me everything including the car. Jerry still makes the cross-member kits. We had all the usual 40 year old vehicle issues. I don't know what he was into the parts for on his end but it was around $2k for us to perform the swap for him. We did EVERYTHING including transferring the timing marks to the EA82 flywheel and all the wiring to make it work like stock.
GD