I have a top loading whirlpool washer that is having issues with agitation. The assembly that comes up the center of the inside that agitates the clothes seems to be in 2 separate pieces. The bottom part will agitate but the top part will not for some reason. It is just spinning freely atop the bottom piece. I cant seem to find where I can disconnect the two pieces and and repair it so that the whole assembly will agitate.Also the spin cycle works fine. PLEASE HELP!