Pulled Agitator straight up and removed the plastic coupling using an adjustable wrench. Cleaned parts and replaced the broken agitator coupling with the new one. Wrenched the new lag bolt in, and put the agitator straight on.
Cleaning took some time as my washer is 14 years old. Replacement took no more than 60 seconds and was cheap! $6.87 and I don't have to buy a new washer!