Dear Robot, 1/ If by friction, you mean 2 surfaces sliding one on the other, I think there is not so much friction in a gear box. If the gears are well designed, the teeth are rolling one one the other, not sliding (involute tooth profile). Same for the bearing inside, the balls are mostly rolling. 2/ Why do I have to confirm I'm not a robot (in the suscrib form) to answer to a robot ??