need help guys. replaced my upper and lower rear control arms on my 91 coupe with some upr non adjustable ones with poly urethane bushings now i am hearing a winding noise inside the car any ideas what that could be?
Now you know why Ford used rubber bushings - they help isolate the noise. If you took the cast iron weight (AKA dog bone)off the bottom of the differential, put it back on. It is a vibration dampener that helps soak up noise and vibration from the driveshaft & rear axle.
When you install the control arms, you must have the jackstands placed under the rear axle. That loads the suspension so that it mimics the way the car normally sits. That way you don't end up with the new bushings in a twisted preload when you tighten down on the mounting bolts. Doing it any other way may cause problems.