I pulled and replaced the chopper and spray arm bearing. The bearing looked "ok", but it is quite old and best to go ahead and replace it while I'm in there. The chopper needed replaced. The blades showed signed of abuse and when I took the chopper out to inspect it, it fell apart. Sadly, this did not fully resolve my noise issues. I'll have to replace bearings or perhaps the sump unit next, when I get up the courage to deal with this stuff again. It's not that hard, but it's a real PITA! Got my part in 2 days by FedEx, at half of what the local parts place wanted.