U-joint?

The press fit certainly does not keep the the thing together it IS the clip. However if you are saying that the cap was "finger tight" it's time to replace the yoke.

Having said that I've seen a few that you could start and push part way in with your fingers, and it did not take much of a "tap or two" to finish seating them.

Also yokes BEND!!! It does not take much to move the sides in/ out from pressing/ hammering and get them more or less in or out of line