My GE Select top load washer is having an agitation problem. When the washer has no clothes in it, it will agitate, but seems to be slipping maybe. When clothes are put in it, it stops agitating, but everything else is running fine. I've checked the agitator and the outside of the coupling and they are fine. I can't seem to get the coupling out, but it will turn a quarter spin with no effort. Any input is appreciated. Thanks