Level of DifficultyEasy
Time to do repairLess than 15 mins
Age of Appliance5 - 10 years
To replace the dogs that cause the ratcheting motion:
I removed the softener cup by pulling straight up. (You've probably found, as I have, that the softener cup and the bleach dispensers are problematic: the softener cup must be cleaned with every use or the old softener liquid turns to glue, and the bleach dispenser mechanism plugs and distributes bleach onto your next load, ruining entire loads of clothes.)
Then I lifted the cap covering the retaining bolt by inserting a screwdriver alongside in the square holes provided, loosening it, and lifting it out.
Then I used a socket and a very long extension to remove the retaining bolt. I lifted the agitator straight up.
The next step can be a problem: I survived it (though I did strain my back). What's required, as you can see by reading the preceding letters, is to lift sharply on the upper agitator while holding the lower agitator with your bare feet or some soft shoes. What this does, at least on my model, is to break off the tabs that are fused together over the ratcheting-dogs, which are the focus of the repair. (These tabs hold the upper and lower assemblies together, moving the dogs assembly with the lower agitator.) In my case, one of the tabs broke off a half inch below the top, but that wasn't catastrophic and I didn't lose the rest of them, so when I reassembled the two halves still snapped back together.
One problem was that when I jerked the two assemblies apart, the parts of the dogs assembly went flying. Everyone had said to make sure everything went back the same way it came apart--for me there was no way to tell what that way was, but common sense tells you which way to reinstall the new dogs; they have to catch every stroke.
To reassemble, position the dogs with the retainer cup inverted. Then hold them upside down while sliding the upper agitator down over them. This holds them in place. When sliding the upper agitator down onto the lower, make sure the slots line up and use a smooth even pressure. Snap the two halves together, bolt the agitator back into the machine, replace the cap with the large o-ring (make sure you clean and/or replace the o-ing), and reinstall the softener cup.
Et, voila! You're back in business.