Removed Agitator, noticed cracked coupler.
At AppliancePartsPro.com:
1) Found my washer
2) Found and ordered the parts. Got an extra belt for a future repair.
3) AppliancePartsPro had a repair video for the coupler.
4) Very fast delivery of order from AppliancePartsPro.
5) Followed the video, 5 minutes later, done.