Vibration

[50fordcoupeman]

My avatar has a 302 coupled to what I believe (by casting numbers) to be a 68 Galaxie manual 3 speed (no OD). There is a very slight vibration but it goes away when clutch is depressed or coasting out of gear. The drive shaft appears to have been balanced and the u-joints are new. There is no play from the tail shaft but there is some play from the yoke when it is slid onto the tail shaft. My question: is there a bushing/bearing that the yoke slides through or does the yoke need to be replaced? It didn't look to me that the yoke slid through anything except a seal.

Thanks for any suggestions.