Limited slip installation.

Factory or aftermarket gear? If Richmond BL setting is ecthed on the ring gear (normally .010). Move the BL to .010 and check rotation. If the tight spot goes away and you know for sure the bearings and races are good more than likely the runout of the carrier is out of limits. I always check the runout on unkown carriers. People beat the ring gears off with hammers instead of using heat to get old ring gears off. A good machine shop can cut the carrier to zero runout.