It is a very close fit, tight even when clean and oily. I use a heavy dead blow hammer, lift the coupler shaft to it's max and smack it outward with the dead blow near the uni joint. As the assembly creeps out it will want to **** off center and jamb. So I tap the gear yoke uni joint to center it up and resume the big smacks on the coupler shaft. I've only had one out of many just slide right out.
I've read on this forum an air heat gun/paint stripper will heat up the nose enough to expand it and ease the operation.
Mine fights me every time on reassembly. Slide in, ****, jamb, tap back on center, continue.