My Jandy Stealth Series Pump (Model SHPF/SHPM) recently began making progressively louder noises that are best described as "grating". I pulled the backplate and diffuser and found the brass lining inside the diffuser was torn to shreds. Here's a pic



I replaced the diffuser and reassembled. The noise has lessened, but is still there. It sounds like something is still grating on something else. Funny thing though, the impellor tube does not show any signs of wear where it extends inside the diffuser.


Any ideas as to what is still happening and how I fix it?