PS fluid level? Not only is it where it’s supposed to be, but is it holding that level also? Might be looking at a failing pump or a blockage in the power steering circuit where a flush and replacement of your return line if it’s cracked would come in handy.
It could also be a generally faulty
rebuild or improper lash setting from the rebuilder in which case you should claim the warranty and try again. I know it sucks to have to redo, but Saginaw box rebuilds are some of the most fickle parts on older GM vehicles along with A/C compressors. Probably others that I can’t think of at the moment.
If the noise is not the “wah” noise that emanates from the PS pump, except maybe if it’s under load and struggling to turn the wheels, my vote is on the latter scenario.