An apparatus for selectively sharing, towards separate users, the power of a multi-drive unit vehicle, includes a mechanical transmission, that connects propulsion units of the vehicle to at least one primary drive unit; a secondary power unit for service units, which is operatively positioned between the mechanical transmission and at least one service unit of the vehicle; as well as at least one of either a first or a second joint, that are mounted on the mechanical transmission on either side of the secondary power unit for service units and are switchable by operating suitable control means.