Abstract: A differential having means (35) operable to limit rotation of an output gear (23) relative to a gear case (11), and actuation means (55) for actuating the rotation limiting means, from an unactuated (FIG. 1) to an actuated condition (FIG. 4). The rotation limiting means includes a member (47), toward one axial end of the gear case and moveable between a first position, the unactuated condition of said rotation limiting means, and a second position, the actuated condition. A sensor assembly is adjacent the one axial end of the gear case and includes a sensor element (71) and a wall-like member between the rotation limiting means and the actuation means. The wall-like member includes a non-ferromagnetic portion (73) between the sensor and the moveable member. Movement between the first and second positions results in a corresponding change in the electromagnetic flux (F) coupling the sensor element and the moveable member.