2003 Chevrolet Trailblazer squealing noise

I have a squealing noise that to me sounds like the harmonic balancer, but I wouldn't think they would do that. I've changed the idler pulley, tension pulley, belt, and altenator with no success. The noise isn't as loud but is still there. I tried taking the belt off and turning pulleys by hand and the altenator was squeaky and changed that like I said. When I spray the belt with wd-40 the noise goes away, but temporarily. Any ideas on what the issue may be? I appreciate any ideas.