Motor was working and rotating lower portion of agitator, but the top was not spinning.

1. Remove the fabric softener receptacle

2. Remove the plastic dome shaped separator with a rubber o-ring around it (directly beneath fabris softener receptacle)

3. There is an 11mm bolt right in the center. Use socket wrench to remove bolt.

4. Remove agitator from washign machine.

5. Separate top half of agitator from bottom half (this was the most difficult part for me; unlike others who have described this repair, mine would not simply pull apart; I spent quite a while trying to pry up the white plastic clips extending from the bottom piece through the clear plastic piece that covers the "dog teeth" that make the top piece agitate)

6. Once apart, replace worn "dog teeth" with new dog teeth.

7. Put back together in reverse order.