Patent ID: 8868308

Claim:
A method for controlling an operation of a coupling means mechanically coupling first and second axles of a transmission system of a motor vehicle, the first axle being driven as standard and the second axle being driven as an option depending on a state of the coupling means, the transmission system being capable of operating in a first mode in which a first maximum value of torque can be transmitted by the mechanical coupling means, or in a second mode in which a second value of torque that can be transmitted by the mechanical coupling means is higher than the first maximum value of torque transmittable in the first mode, the method comprising: operating, by a control system, the transmission system in the first mode, and while operating the transmission system in the first mode, determining a required torque value, determining a first difference in speed of wheels of the first and second axles, and determining a first speed of the vehicle; and changing, automatically by the control system, an operating mode of the transmission system from the first mode to the second mode when the following conditions exist together: the required torque value is equal to the first maximum value of torque transmittable in the first mode, the first difference in speed of wheels of the first and second axles is higher than a first threshold, and the first speed of the vehicle is lower than a first speed threshold.