GSD900X-70BA GE Dishwasher, cannot remove lower spray arm, it won't unscrew and there is no tab on the back of the base that I can press on with a flat head screwdriver to release. I have been (per instructions I found elsewhere) unscrewing it for a week, counterclockwise. Should I be doing it clockwise, is there a bolt or a nut holding it on? Any help is appreciated. Thanks.