I put a lift on my 87 Jimmy (full size). The truck ran great prior to the lift. The rear end started make a grinding rachety noise in the ass end when I decelerated. I put shims (6 degrees of angle)on. It seemed to help a little, but not much. I highly doubt anything is wrong with the rear diff (10 bolt) since it was fine before the lift. I'm would like some more ideas on what could be wrong. The angle of the driveshaft isn't that bad. Would an out of balance driveshaft cause this noise? By the way its a 10" lift. The front driveline is at a much worse angle and it operates great. I would appreciate any news thoughts. I have read past posts and they don't give me quite the help I need.