A gear unit includes a shaft, in particular an input shaft, a flange part and a housing part. The input shaft is supported by bearings in the housing part, and a fan is connected to the shaft in a torsion-proof manner. The housing part includes cooling fins, in particular cooling fins that extend in the axial direction, i.e. in the axis direction of the shaft, the cooling fins have an offset and/or stepped configuration, and the flange part surrounds the offset or stepped region of the cooling fins, in particular in the manner of a housing.