Trying to diagnose a motor problem from a bad sound none of us has heard . . . is not a good idea.

And, even if you recorded and posted the sound, that wouldn't help, because we'd need to be able to match sound with the visually examined source.

OTOH, if you want to take pictures of the pump parts -- impeller, diffuser, etc. -- and post them somewhere (does Yahoo have some thing like Picasa? -- if not make a Google account, and use Picasa), and give use the URL address, that might help.

OR, borrow a pump from your friend, connect it temporarily and see if the sound disappears.

PoolDoc