A differential control system for a motor vehicle such as a truck including at least one differential includes at least one differential lock which is able to operate the differential into at least a locked or an unlocked state, a controller that controls the differential lock, a manually operable control member freely rotating bidirectionally around at least one axis, an encoder connected to the control member to convert a rotation of the control member into a signal fed to the controller which controls the differential lock in order to operate the differential into a locked or an unlocked state.