I can't get the spray arm to stay attached. I can press it onto the screw, but whichever direction I turn, it doesn't really get attached. How do I get it to stay attached? I got it to attach for a few loads and it worked really well, but now it won't stay attached. If I stop the load in midwash and pick up the spray arm, it just comes right off.

Thanks, but that didn't help. I disassembled it, put it back together. Here's what happens: if I stop the dishwasher during the cycle and reach in, I can just pick the spray arm up off the screw. It sits over the screw but isn't firmly attached. Is it supposed to be firmly attached, or am I supposed to be able to just pick it up?

The spray arm does stay over the screw and spin, but it doesn't seem to be distributing water anywhere, certainly not to the top rack. Would that be caused by it not being affixed to the screw? If so, is it possible the part of the spray arm that affixes to the screw might be stripped?