I've searched the threads and see a lot of posts about squealing, grinding and rubbing noises related to brake pads, belt, etc. but don't know if mine is the same - at slow speeds (only time when I can hear it) I get a Whoo Whoo Whoo sound from the rear but can't tell which side. It's not affected by pullng the brake or clutch. Does anyone know what this is? I've heard it before but now it's getting much worse. Thanks for any opinions!