I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.
I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.
Please note, I am just a moderator for this category, I can only try and find experts to help, I can't answer the question itself.
Sorry for delay in replying. I do not know what to say further - once initial screech stops mower continues and cuts grass satisfactorily. The only similar noise I have ever heard is when in winter some cars appear to have a slipping fan belt.
Is this any help?
We will continue to look for a Professional to assist you.
Thank you for your patience,