There is weep hole from the cup to the rear differential. Moly paste will plug this hole and cause premature failure of your drive shaft. USE ONLY GREASE HERE. You've been warned. I had two failures here before realizing the dealer used paste and plugged this hole during a warranty repair.

I was leaving on a trip and had to get a different rear end to fix the problem as I did not have time to rebuild. Check the old archives if in doubt.