A method of operating an articulated machine includes sensing an articulation angle and a wheel steering angle of the machine, and controlling a locking state of a differential responsive to a steering radius of the machine. An articulated frame wheeled machine is further provided, and includes a front frame unit with a wheel steering apparatus, a back frame unit and an articulation apparatus coupled between the front and back frame units. First and second sensors are operable to sense a wheel steering angle and an articulation angle of the machine, and an electronic control is provided which is configured to selectively lock or unlock a differential of the back frame unit responsive to a steering radius of the machine.