A gas turbine engine is provided, comprising a tail cone and a low-pressure spool outside the tail cone. An input shaft may be coupled to the low-pressure spool and inside the tail cone. A differential may be coupled to the input shaft and inside the tail cone. A generator may be coupled to the differential and also disposed inside the tail cone. An oil pump may be configured to pump oil through the generator to the differential. A generator assembly is also provided. The generator assembly may comprise an input shaft, a differential coupled to the input shaft, a rotating transfer tube coupled to the differential, a generator coupled to rotating transfer tube, and an oil pump configured to pump oil from the generator, through the rotating transfer tube, and into the differential.