I rebuilt my sc10 ball diff and its working like video says it should. Both cups are spinng same direction. The old gear the cups spin opposite direction. Ive tried everything that my noobie mind can think of. Did I assemble it wrong I followed the video to the tee. I didn't sand rings when I spin the big gear with fingers its smooth as can be but I install it withe the two other gears in diff housing it binds up or has a thunk in one spot. Should I just break down and buy a assembled ball diff for $50. Thanks for reading my thread Kenney