The levelling auger unscrews out of the u-joint and the u-joint also unscrews from the shaft. last time I was in there it came apart fairly easy, just a bit of an awkward place to work. Good luck with it.
Winona Attrition Mill 1009 W 5th St Winona, MN , 55987-5126 Phone: 507-452-2716 Take your auger there and they will cut old flighting off and weld new on while you wait. Call ahead to make appointment. Ask them to balance that auger too. Will make for a much smoother running fill auger.
Might check into AGCO chrome replacement or getting yours chromed after reflighting, this auger gest scrubbed more than any other on the machine lifting nearly straight up. Mine was replaced with AGCO chrome, dont ever plan on toughing it other than a bearing. Grease that double u-joint good, dont use cheap grease will cost you money. Good luck