S'cuder said

It looks really dry. I always lube them up. Some nice gooey, tacky grease might help.

Also, maybe try taking the shoes off and flipping them over. It looks like they maybe on wrong. Flat part towards shaft, curved part towards coupler. See this picture from a service bulletin.

View attachment 1716149892

Here's another picture I just found on FBBO. The drawing PY22 on which this is based shows a "less assembled" version of the above. Note the shape of the shoes and how they're oriented on the pin. I think yours may be assembled differently. I'm not sure, it's hard to see in your picture. For now, ignore the stuff about the master spline.
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