If you mean the round piece that the upper elbow is screwed into, that's the end of what most guys call the banjo. The inner end is around the shaft. The part you see comes through a hole in the cover and is sealed with an O-ring. Mine leaks there. You have to pull the cover to replace it. I cleaned the oil off best I could and forced silicone into the seam till I can get it fixed. Still leaks but not so bad. Just keep the fluid topped up.