I know this has been addressed before, any new help would be great. I am pulling my hair out. I bought a set of new Motive gears 3:55 for my Chrysler 8 3/4 diff.(489 case) I have had the carrier in and out 2 times, and apart atleast 30 times.After the last adjustment, I get a whine at 40-50 mph gas half on, half off (sort of coast).Lower and higher speeds, it is pretty quite, but still there. Before the last adjustment it was at 30-40 mph.That was at plus .012 pinion out .042 total shims) I have all the correct tools,pinion depth finder, dial indicator, and digital calipers.I have done diffs before.I am using prussian blue to check the pattern. Starting with the correct depth of 2.767 on the pinion, I have tried every depth at .002 intervals all the way to .030 behind the pinion (total of .052 shims). The best spot I have found was .050 (+.028 additional from 2.767) . I have the back lash at .009 which seems to be the best (Motive gear wants to see .008-.012 BL). My pattern always shows heavy to the tow, but with this last set up (.050), I got the coast pattern centered in the middle of the ring gear, and the drive still a little low towards the tow.If I went any further (pinion deeper .052) I get the drive going deeper to the tow. Man, what is up with this? Any help?I know this isn't rocket science!