A transmission for a wind turbine has a planetary gearset with a fixed sealing surface and at least one cavity. The gearset includes a rotating planetary carrier or a rotating ring gear. The cavity is fixed relative to the carrier or ring gear and has at least one opening. The transmission has an oil reservoir. The carrier or ring gear can rotate to at least three positions. By rotating, the carrier or ring gear can move from the first to the second position and from the second to the third position. In the first position of the carrier or ring gear, oil can flow from the oil reservoir through the opening into the cavity and in the third position the oil can flow through the opening out of the cavity. In the second position of the carrier or ring gear the opening is closed by the sealing surface.