A gear unit having a shaft, particularly an input shaft, a fan impeller being joined in rotatably fixed manner to the shaft, a fan cowl, which at least partially surrounds the fan impeller, being mounted on the gear housing, a separating plate for separating the pressure chamber of the fan from the suction chamber of the fan being joined to the fan cowl, the separating plate having an air inlet for the fan impeller and being disposed on the side of the fan impeller facing away axially from the gear unit.