2 piece driveshaft ... grease/dust shield for slider yoke?

[brimac50]

I'm replacing the center U joint on my old '80 3/4T.  On the front of the center slider yoke, there is a threaded collar, that appears to hold a grease seal.  Whatever was originally there has broken up, so it's not identifiable. Parts man said it should be a felt dust seal.  Is he correct, or should it be an actual rubber seal of some sort?     Appreciate the help. Thanks

[KoolerSL2]

mine was a rubber seal.
i havent been able to find one yet.
all i do now is everytime i change the oil i grease that slip.

[VileZambonie]

Any driveshaft shop should be able to hook you up.

[brimac50]

Acquired a Spicer D3A dust cap kit today from a "local' drive shaft shop. The new seal is made of thick cork.  Problem should now be solved.