A close up of a 737NG flap transmission with the movement of the torque tubes and gearboxes. The close up is of transmission #4 and the flap track of the left inboard flap with the flap rollers. In this video the flaps are selected from up to 40 units. For 737 technicians a daily view, but for others a view they never see, or only hear a little when sitting in the cabin as a passenger.