Front Driveshaft Non-Greaseable U-Joints?

[NJBronk]

I didn’t reinstall my front driveshaft after doing the suspension; I figured I would grease it before putting it back on. I know nothing about these things and have been trying to read/learn.

I greased the slip joint using the zerk, but don’t see any fittings on either end. The silver cap came right off one side (put painters tape to hold it on); do I just remove them and pack some grease in there? What about the double cardan end?

How do I determine if/when the U-joints need to be replaced?

 

[Broncobowsher]

lubed for life. Generally really good. I have several that are nearing 200k and are still fine.
They are built with the correct amount of the correct grease. As long as the seals stay good (not blown out from someone over greasing it for example) they are known for lasting over 500k.

 

[Steve83]

In the 70s & 80s, most automakers learned that the act of greasing things was CAUSING more problems than it prevented. Dirt being pumped in; seals being ripped apart by too much grease, which then allow most of that grease to leak out & contamination to flow in... That's why most of them switched to sealed U-joints & other parts; not only are they physically stronger than those with grease fittings & journals; they last MUCH longer, with no maintenance. Count yourself lucky.

And to answer your question: you'll know when you see or feel a problem in them (during the regular maintenance inspections that you SHOULD be doing on-schedule). You can put a SMALL amount of grease in the cap that slipped off, IF it appears to be getting dry. But don't "pack some in there".

The Ford TSB on this page (which might be undergoing site maintenance, but it's safe) explains more:

(click this text)

 

[NJBronk]

Thanks!