wierd humming/whinning sound in rear of car

Good evening all! About a week ago, i started hearing this wierd humming or whinning sound coming from my 1993 320i. It gets louder as you pick up speed, and quieter when you slow down. Its hard to describe the sound, its just a constant higj pitched sound that has never been heard before. It has increasingly gotten louder too. Any ideas on what it could be? Your help is greatly appreciated. I tried to search for something similar on the threads, and didnt find anything.

Barak Obama has been secretly initiating fuel saving device installation with the help of the Secret Service autopool maintenance department (SSAMD) and may have surrepticiously added a Hybrid Power Generation Supply System (HPGSS) in the trunk of your car. Check for a small cage with a wheel and several trained chipmunks (Alvin, Theodore, and some other guy) peddling their little hearts for you and the Fatherland. The humming should be at low RPM and the Whining would obviously be at High RPM. Be kind to them, they don't eat much.:naughty:

Probably your wheel bearing(s). If it's coming from the rear, it'll be rear wheel bearings. To see which one, listen as you turn left and right. If it DECREASES when you turn right . it's the left rear wheel bearing and vice versa. Turning the car UNLOADS the bearing enough to quiet it down. They are not cheap...at least the labor won't be cheap :)

try to check the fluid level in the rear end, drain and replace the gear dope see if it quiets down, if it dosent, do what frank suggested about the wheel bearings. is it front wheel drive? you said it was a 93, not sure about that year, my 85 318i is rear drive. good luck

Most 3 series BMWs are RWD...maybe all. I'm not that much up on BMW history.