Rockwell Sq100 - very high backlash

Ok there might be your problem. A Rockwell diff has enough backlash in the gear set and slop in the input an automotive guy would think their beat to death when they’re new. Not sure about the internal measurement in a 46k but fresh you can spin the shaft 20 or 30 degrees easy and, the input feels like there’s an 1/8” of play in it.

 

Those rear ends will tell you when that bolt is right if you know what to listen for. Run that screw in until it just touches, then back it out a 1/4 turn and lock it. If you hear a funny little “tink” noise out of the diff when you lift real hard it’s right. If you lift off loaded uphill and DON’T hear that noise, it probably should be moved in a bit. You just don’t want it touching. That builds heat.