For once, Murphy's Law didn't rear it's ugly head. I simply removed the top cover cap, unscrewed the 10mm fastener, removed the old agitator and replaced it with the new one. Bingo! Total repair time: 2 minutes. Saved an appliance service call and possibly removing a washer from the second floor. Total of 24 hours from diagnosis time (thanks YouTube) including the 20 hours of shipping time to receive the part.