The invention relates to a backlash-free planetary gear unit with a sun gear and with a ring gear, which mesh with at least one first planet gear of a planetary stage, wherein the planetary stage comprises a first planet carrier on which the first planet gear is rotatably mounted, wherein there is furthermore at least one second planet gear in the planetary stage that also meshes with the ring gear and the sun gear, wherein the at least one second planet gear is rotatably supported at a second planet carrier of the planetary stage, wherein the two planet carriers are in the circumferential direction of the sun gear preloaded relative to each another such that also the at least one first planet gear is preloaded relative to the at least one second planet gear in the circumferential direction of the sun gear.