How to Troubleshoot & Replace Whirlpool AP6008106 / WP3363003 Upper Agitator

I replaced it . 

Ordered the parts, which arrived in just two days, and fixed it in accordance with the instructional video and it went smoothly. Everything working within specified parameters. No sweat. 

I emailed Joe Martin and he advised on the repair. Even after spraying the bolt holding the upper agitator in place with PB Rust Blaster and letting it soak, then tapping with hammer. Bolt would not budge. I used a combination of a sawzall and dremel tool to cut away the upper agitator. It was still impossible to get a good grip on the lower agitator, so I put a 4" C clamp on it and used a 1x3 for leverage so I could hold the lower agitator with my left hand while applying pressure to a 1/2" drive, 7/16" socket with my right. This worked as the bolt finally budged and I was able to get it apart. Replacement of the parts, once the bolt was out, was thankfully very simple. The washer works fine and the repair saved me from having to spend several hundred dollars on a washer. 

Followed online repair video. 

Took it apart and determined parts needed. Parts breakout and repair video very helpful. 

I watched the video and even with a stubborn top bolt I was finally able to get the bolt off. However, I did take the back off to see if I could place a channel lock on the shaft but I couldn't do it. I fixed it but didn't try the washer yet. But I' sure it will work now. Thanks. 

Take off upper agitator arm and replace the short cam agitator. put it back together and tested.