A commercial automotive vehicle comprising at least one shaft associated with at least one auxiliary engine equipped with a reducer assembly associated with a differential, wherein the differential is a free differential assembly, being associated with the shaft and associated with at least one torque transmission coupling and/or decoupling device between said auxiliary motor and the shaft, wherein the coupling and/or decoupling is in response to at least one signal sent by a control system of the device, wherein the at least one torque transmission coupling and/or decoupling device comprises a mechanism for coupling and/or decoupling the torque transmission comprising an actuator connected with a displacement shaft and a motion transmission fork connected to the displacement shaft, said actuator displacing the motion transmission fork by means of the displacement shaft.