A gear unit with fan assembly, wherein the fan assembly has a fan impeller, a cowl and a grille, wherein the fan impeller is connected non-rotatably to the input shaft of the gear unit, wherein the fan cowl is fastened to a holding frame which is fastened to the housing of the gear unit, wherein the grille is formed of two grille parts (3, 4), wherein the cowl is formed of two cowl parts, wherein each grille part (3, 4) is connected to each of the two cowl parts (1, 2), characterised in that - the grille parts (3, 4) are each formed as a polygon such that the contacting face between the respective grille part (3, 4) and the respective cowl part (1, 2) in each case is composed of planar face pieces, - or in that between the two grille parts (3, 4) a first parting line is formed as a straight section or as two straight sections which lie flush with each other, with between the two cowl parts a second parting line being formed as a plane curve composed of straight section portions, with the first parting line and the axis of rotation of the input shaft spanning a first plane, with the second parting line and the axis of rotation of the input shaft spanning a second plane, with the second plane being oriented perpendicularly or at least being at an angle of between 30° and 90° to the first plane. wherein the fan assembly has a fan impeller, a cowl and a grille, wherein the fan impeller is connected non-rotatably to the input shaft of the gear unit, wherein the fan cowl is fastened to a holding frame which is fastened to the housing of the gear unit, wherein the grille is formed of two grille parts (3, 4), wherein the cowl is formed of two cowl parts, wherein each grille part (3, 4) is connected to each of the two cowl parts (1, 2), characterised in that - the grille parts (3, 4) are each formed as a polygon such that the contacting face between the respective grille part (3, 4) and the respective cowl part (1, 2) in each case is composed of planar face pieces, - or in that between the two grille parts (3, 4) a first parting line is formed as a straight section or as two straight sections which lie flush with each other, with between the two cowl parts a second parting line being formed as a plane curve composed of straight section portions, with the first parting line and the axis of rotation of the input shaft spanning a first plane, with the second parting line and the axis of rotation of the input shaft spanning a second plane, - the grille parts (3, 4) are each formed as a polygon such that the contacting face between the respective grille part (3, 4) and the respective cowl part (1, 2) in each case is composed of planar face pieces, - or in that between the two grille parts (3, 4) a first parting line is formed as a straight section or as two straight sections which lie flush with each other, with between the two cowl parts a second parting line being formed as a plane curve composed of straight section portions, with the first parting line and the axis of rotation of the input shaft spanning a first plane, with the second parting line and the axis of rotation of the input shaft spanning a second plane, with between the two cowl parts a second parting line being formed as a plane curve composed of straight section portions, with the first parting line and the axis of rotation of the input shaft spanning a first plane, with the second parting line and the axis of rotation of the input shaft spanning a second plane, with the second plane being oriented perpendicularly or at least being at an angle of between 30° and 90° to the first plane.