A method for producing a gear unit, wherein the gear unit has a housing and a shaft with at least one bearing, wherein the housing has a lower part and an upper part which can be fitted on the lower part, wherein the housing has a bearing seat for receiving the bearing, wherein a first partial region, in particular a first half, of the bearing seat is formed on the lower part and a second partial region, in particular the other half, of the bearing seat is formed on the upper part, wherein the bearing is embodied as a rolling bearing and has an inner ring, rolling elements and an outer ring, wherein in a first method step the bearing is mounted on the shaft and the outer ring of the bearing is limited in the axial direction by a retaining means (4, 5, 6) fastened to the shaft, in a second method step, the shaft plus bearing and retaining means is placed in the lower part, the bearing, in particular the outer ring of the bearing, is received by the first partial region, in a third method step, the upper part is fitted on the lower part and is connected to the lower part, in particular by means of screws, wherein the bearing is received by the first and the second partial region, in a fourth method step, a shim ring is laid on the outer ring, in a fifth method step, screws are screwed into in particular axially directed threaded bores in the housing, in particular in the lower part and the upper part, wherein the screw heads of the screws or washers mounted on the screws protrude radially inwards on the housing such that the shim ring is limited by the screw heads or by the washers, in a sixth method step, the retaining means is removed and a bearing cover is connected to the housing, which bearing cover axially limits the shim ring, in particular and hence the outer ring. wherein the gear unit has a housing and a shaft with at least one bearing, wherein the housing has a lower part and an upper part which can be fitted on the lower part, wherein the housing has a bearing seat for receiving the bearing, wherein a first partial region, in particular a first half, of the bearing seat is formed on the lower part and a second partial region, in particular the other half, of the bearing seat is formed on the upper part, wherein the bearing is embodied as a rolling bearing and has an inner ring, rolling elements and an outer ring, wherein in a first method step the bearing is mounted on the shaft and the outer ring of the bearing is limited in the axial direction by a retaining means (4, 5, 6) fastened to the shaft, in a second method step, the shaft plus bearing and retaining means is placed in the lower part, the bearing, in particular the outer ring of the bearing, is received by the first partial region, in a third method step, the upper part is fitted on the lower part and is connected to the lower part, in particular by means of screws, wherein the bearing is received by the first and the second partial region, in a fourth method step, a shim ring is laid on the outer ring, in a fifth method step, screws are screwed into in particular axially directed threaded bores in the housing, in particular in the lower part and the upper part, wherein the screw heads of the screws or washers mounted on the screws protrude radially inwards on the housing such that the shim ring is limited by the screw heads or by the washers, in a sixth method step, the retaining means is removed and a bearing cover is connected to the housing, which bearing cover axially limits the shim ring, in particular and hence the outer ring.