Yes, exactly. WD-40 is not a real lubricant (grease or oil), in
reality, so one needs to replace it with something permanent, at some
point. I've been messing with this old one I have, at the moment. The
WD-40 made it somewhat better but the old grease is still flaking out.

Beings that this one is a goner, anyway, I tried to "open it". I guess
I have to agree with the sage advice I once got. It appears it is
sealed or maybe that hex-shaped end threads on to the mounting threaded
end? It looked like it might. But, no... it won't come apart and all
I've done is make it far worse. Don't try this with yours or it'll end
up like this one!!! hi!!

Just try and lubricate it externally.