Interesting... we're upgrading my entire rear to 31 spline tonight. Mine started making a terrible noise. With the car up in the air, you can physically move the rear wheel up and down. So I know the bearings are shot. My wheels also wobble when in gear and up in the air. Figure the axles are bent. I had the bearings changed back in the day... they were pitted, but they made it for 4+ years that way.