Another rear end noise

I would put the car on jack stands and run it in gear. It could be a bearing which may not make noise without a load on it. Have the gears or diff been replaced or is it all stock?

I would get it in the air then so you can run it in gear while looking at it. Make sure the front tires are chalked though. Check for bearing play at the wheels & exhust or tires rubbing. Also take a long screwdriver and put the handle to your ear with the point on the diff cover (while it's running) and listen for the noise. If it's in the rear end it will be louder then. Make sure you check the u-joint too for slop.

DON'T use a jack to hold it up. I don't want your familiy pissed at me for you getting squished OK.