The top portion of the agitator is not working (the lower part seems to be alright). How do you properly remove the cap #AP3094452? Could you suggest which part(s) might need replacement?
If there’s a ring (usually blue) near the top of the agitator, push it down to unlock the top cap. Otherwise, just pop it off. This will expose the dust cap you mentoned in your post. Pull it out to access the nut that holds the agitator to the shaft.