A process for actuating a hydraulic storage device (5) of a transmission unit comprising a storage space (9) whose volume can be varied between a minimum and a maximum. The volume of the storage space can be changed by acting upon the storage space with pressurized hydraulic fluid from a pressure supply (19) of the transmission unit. To overcome a restoring tendency of the hydraulic storage device, the pressure is set to a threshold value. A holding device (12) holds the hydraulic storage device at least in the operating condition that corresponds to the maximum volume of the storage space against the restoring tendency. The storage space is acted upon by the pressure supply with a pressure corresponding to a threshold value (P_threshold) until the hydraulic storage device reaches the operating condition in which it can be held by the holding device.