I was rebuilding spare diffs as well and I got the hd and old style diffs mixed up so Im going to switch back to the hd and then see what happens ( if it needs shimmed or not ) I tried shimming the pinion on the old style diff and it was too tight , I did have an extra diff that was messed up and I figure that this was the one ... the grub screw on the rr pinion & outdrive was stripped and this all has gave me time to cut that off and change as well ... thanks INTEGRA !