A controllable differential system for a vehicle includes a differential that may be disengaged or engaged, and may further be locked when engaged. A differential lock switch has three positions for sending commands to an actuator for disengaging or engaging the differential and for sending commands to a controller for unlocking and locking the differential. The vehicle includes a motor, a transmission continuously connected to a rear drivetrain, and the differential mounted in a front drivetrain. The vehicle may be driven in rear-wheel drive mode when the differential is disengaged or in four-wheel drive mode when the differential is engaged. The vehicle may enforce a vehicle speed limitation or an engine speed limitation when the differential is locked while a manual override control is not activated. The vehicle may implement an anti-lock braking system that may be disabled when the differential is locked.