Welcome, I'm Chris (aka Moose) I'm an independent contractor here at Just Answer.
I assume you hear this noise while driving as well?
Can you use a stethoscope to listen to to the brake caliper, hub bearing, and output shaft seal to see if they are to blame for the noise prior to having the gearbox removed and rebuilt.
Thanks for asking your question and letting me try to help you.
You should see a rating screen if I have posted an answer, not for an info request.
Your rating is my feedback. If I don't get feedback from customers, I will not be able to continue helping customers here.
Rating me good, bad, or not rating at all does not effect the fee you have paid nor does it close the post.
Follow up/Reply as many times as needed.