A gear unit having a drive element with a first tooth structure, an output element with a second tooth structure, wherein the tooth structures are able to be brought into engagement cogging with each other to form a gearing in at least one engagement area of the second tooth structure. The output element has at least one uncoupling area, in which the cogging engagement of the gearing is uncoupled. The first tooth structure has at least one first modified tooth element and the second tooth structure has at least one second modified tooth element wherein by a movement of the drive element, synchronization of the second modified tooth element with the first modified tooth element is possible in order to create a change from the uncoupled state to the engagement state.