Abstract: A cylinder-capacity selector for a hydraulic motor having at least two active operating cylinder capacities and comprising having at least two main ducts. The selector includes three ports and distribution ducts of the motor to establish selective communication between the main ducts and the cylinders of the motor. When the selector passes between its first and second stable positions, in at least one displacement direction, an intermediate stage exists that is maintained for a lapse of time, during which all three ports are in communication and the section of at least one of the passages between the first and second ports and between the second and third ports of the selector is constricted.