I have an 86 sabaru rx turbo, it runs relly nice but at lower speeds between 5-25 it sounds line the the rubber bushings that squeek when you push the bumper down while the car is sitting. After 30+mph its gone and i dont hear it anymore until i slow down again. Any thoughts. Have looked under the rear and i see a small leak on the rear diff but nothing out of the ordnary please help and all suggestions are welcome