Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
It's the oil gallery end plug Ted. It fits in the alternator end with the 'pip' being held in place by the alternator casting. Make sure you renew the O-ring👍.
And dont try starting the engine without the generatorcasing on or you will e trying to find that plug along with using bags of kitty litter