Look at the starter bendix gear. It's possible that's what's rubbing against the flywheel, making it sound like converter noise.
It happened to me years ago on a rebuilt starter. Installed it, then hearing a scraping noise. The starter that was replaced made no noise.
Pulled off the rebuilt starter, looked at the bendix gear, saw some scraping. I put the rebuilt starter next to the bad starter. I noticed the bendix gear on the rebuilt unit was a little more forward than the gear on the original starter .The rebuilders shimmed the bendix gear too much.. Swaped out the starter with another one making sure the bendix gear was positioned correctly. After that no noise.
Hope this helps.