A vehicle driveline assembly (10) for an automotive vehicle includes a differential assembly (26) adapted to transfer torque proportionally between first and second axle half-shafts (28,30). An over-running clutch (34) is adapted to selectively lock the differential assembly (26) thereby effectively rotationally locking the axle half shafts (28,30) to one another. The differential (26) has three modes of operation; an open mode, wherein the differential is kept un-locked; a locked mode, wherein the differential is kept locked; and an automatic mode, wherein the differential is locked or un-locked based upon predetermined operating parameters. A selector switch (90) allows an operator to selectively place the differential (26) in one of the three modes. An electronic control unit (92) receives inputs from the vehicle, compares the inputs to pre-determined operating parameters, and selectively engages or disengages the over-running clutch (34) when the differential is in the automatic mode.