The gearbox is constructed for transmission of the high drive output, and due to its specified small installation space, with double helical teeth. The special bearing on the gearbox output side can accommodate the axial force of the extruder screw. Lubrication of the precision bearing and the highly loaded gear meshing via a single-motor driven oil lubrication system. Lubrication system consists of electric motor, oil pump, oil cooler, double switch filter and monitoring of flow, pressure and temperature. The bearing temperatures are measured individually on each bearing location.