Hey junkman... were you drinking when you wrote this???:cheers: lol!!!First, welcome to the forum. You should introduce yourself. :buhbye:
Could the car be low on gear oil? Sure it could. Anything is possible but the question is, have you checked it? The car has to be in the air and level to do so. Do you know how? That is step one so that you can eliminate the easy to check problems first. Also, it could be the fuel pump that you hear. It winds too and the pitch changes with your speeds. Last of all, it may be a wheel barring.
One thing that you need to do is edit your profile to include the year and car you have. This will assist folks who are trying to assist you.