Upper agitator is fastened correctly but does not move with motion of bottom agitaor unless you place mild downward pressure
Most likely the cause of the problem are the worn agitator clutch dogs.
You can find the complete instructions in the one of my previous posts: http://forum.appliancepartspros.com/washer-repair/525-top-agitator-slipping.html
In order to provide the right part numbers I need the complete model number of the washer.
Gene.