Update: Never found out what part 2 is called, but I reached down to disconnect the swtich and #2 just flopped over. I could move it back and forth very easy, and the threads had oil leaking. Seems the PO changed the sending unit and switch but never tightened this up. removed the sending unit, spun #2 off, put a little teflon tape on it, put it back in, reattached the switch and sending unit, cleaned everything off and went for a ride. 30 miles later, no oil. Love cheap and easy fixes.