One more issue with the OBX diff that I forgot to note in my previous post... The shoulder of the ring gear mount on the OBX casing, where the ring gear should have a press-fit, was 0.002" smaller than the inside diameter of the ring gear. I tried mounting the gear to see if the ring gear bolts would self-center the ring gear. But it didn't happen. I then began to think of ways I could shim the ring gear against the case so it would center properly. I decided to work with a section of 20-gauge steel wire (solid) because I had it on-hand. Basically, I took a length of wire just shorter than the circumference of the diff case at the ring gear flange/mount and wrapped it around the base. Then I set the ring gear over it and tucked the wire into the chamfered edge of ring gear, which meets the corner of the flange and case. This bit of wire filled the gap between the corner and the flange. And when I bolted the ring gear down, the wire acted like a shim that was a crush-fit. It worked pretty well, bringing the measured runout down to 0.001". It isn't ideal. But it worked. And that bit of wire will not slip out of place - no way for it to move at all... <img src="/forums/images/graemlins/kewl.gif" alt="" />