A first planet stage of an epicyclic gearbox revolves in a gearbox housing and includes a planet support having two interconnected side pieces. Planet gears are borne in the planet support via planet gear bearings and engage a central sun gear shaft and a hollow gear secured to the gearbox housing. A first channel has one end connected to an oil supply in communication with an oil feed pump and passes through a gearbox housing wall, and another end connected via second channels, passing through one side piece of the planet support, to third and fourth channels, passing through the shafts of the planet gears and open to the planet gear bearings. The first channel passes through an insertion apparatus secured in the gearbox housing and. The first planet stage is complemented by a second planet stage with a second planet support, second planet gears and a second sun gear shaft, with the insertion apparatus including a radial stator with an axial bush arranged radially between the first and second planet supports.