Transmission system for a motor vehicle, comprising: - a first element and a second element movable in rotation with respect to each other about an axis X, one of the first and second elements (4, 5) being intended to be driven by a motor and the other of the first and second elements (4, 5) being intended to drive at least one wheel shaft (2, 3) of the motor vehicle; and - a coupling device which comprises: - a first coupling part which is locked in rotation with the first element and a second coupling part which is locked in rotation with the second element, the first coupling part being movable with respect to the first element between a coupled position in which the first coupling part is coupled to the second coupling part to transmit a torque between the first element and the second element and a decoupled position in which the first coupling part and the second coupling part are decoupled from each other, characterized in that the transmission system further comprises: - a disc which comprises a fixing region which is fixed axially to the first coupling part, the disc comprising an annular portion forming a target and at least one elastic return portion which is configured to deform elastically during the movement of the first coupling part from the decoupled position to the coupled position and to exert a return force capable of elastically returning the first coupling part to the decoupled position. - a first element and a second element movable in rotation with respect to each other about an axis X, one of the first and second elements (4, 5) being intended to be driven by a motor and the other of the first and second elements (4, 5) being intended to drive at least one wheel shaft (2, 3) of the motor vehicle; and - a coupling device which comprises: - a first coupling part which is locked in rotation with the first element and a second coupling part which is locked in rotation with the second element, the first coupling part being movable with respect to the first element between a coupled position in which the first coupling part is coupled to the second coupling part to transmit a torque between the first element and the second element and a decoupled position in which the first coupling part and the second coupling part are decoupled from each other, characterized in that the transmission system further comprises: - a disc which comprises a fixing region which is fixed axially to the first coupling part, the disc comprising an annular portion forming a target and at least one elastic return portion which is configured to deform elastically during the movement of the first coupling part from the decoupled position to the coupled position and to exert a return force capable of elastically returning the first coupling part to the decoupled position. - a first coupling part which is locked in rotation with the first element and a second coupling part which is locked in rotation with the second element, the first coupling part being movable with respect to the first element between a coupled position in which the first coupling part is coupled to the second coupling part to transmit a torque between the first element and the second element and a decoupled position in which the first coupling part and the second coupling part are decoupled from each other, characterized in that the transmission system further comprises: - a disc which comprises a fixing region which is fixed axially to the first coupling part, the disc comprising an annular portion forming a target and at least one elastic return portion which is configured to deform elastically during the movement of the first coupling part from the decoupled position to the coupled position and to exert a return force capable of elastically returning the first coupling part to the decoupled position. - a disc which comprises a fixing region which is fixed axially to the first coupling part, the disc comprising an annular portion forming a target and at least one elastic return portion which is configured to deform elastically during the movement of the first coupling part from the decoupled position to the coupled position and to exert a return force capable of elastically returning the first coupling part to the decoupled position.