US Patent 7930953 Gearbox with removable oil tank

A gearbox for an auxiliary power unit (APU) includes a front side defining a generator interface configured to be coupled to a generator, the front side further defining an oil pump and fuel control component interface configured to be coupled to an oil pump and fuel control component, and a starter interface configured to be coupled to a starter. The gearbox further includes a back side on an opposite side to the front side and configured to house a gear train; a bottom side defining an oil tank interface configured to be coupled to an oil tank; and a debris conduit extending from the generator interface to the oil tank interface.