Abstract: An apparatus and method according to the present invention actively monitors and controls the preload and rolling bearing resistance of angular contact pinion bearing sets for power distribution devices, such as axle pinion bearings, differential case bearings, power take-off units and the like. A hollow spindle is engageable with a drive flange for rotating a shaft. A central spindle is disposed coaxially with the axis of rotation of the hollow spindle and is sheathed within the hollow spindle. The central spindle has a socket engageable with a nut mounted on one end of the shaft for adjusting end play. Intermeshing gear teeth are interposed between the hollow spindle and the central spindle for driving the central spindle in rotation with the hollow spindle while allowing incremental rotation of the central spindle to adjust end play. First and second digital sensors monitor rolling drag resistance and torque applied to the nut.