After ripping the torn boot off, crud starts getting up in there. No zerks, so every once in a while you pull the shaft apart to clean and re-grease.

I haven't tried 5th wheel grease, just whatever I grab from the local autoparts stores. (usually lucas red n tacky)

 

my boot is not torn, but I suspect there may be little if any clean grease left on the splines if that is how they are supposed to be (bought the jeep used and it was definitely in the water/mud from the PO)

Guess I will check this part of the DS when I go to lube up the Rzeppas also