This animation uses a rotation script for the gears like this:
( eulerAngles 0 0 (360*currenttime/100) ) as quat
This can be customized by either changing the 360 to a larger number of degrees to speed up the animation, or by changing the 100 to match the number of frames in the animation. Balls are linked to the gears so that their rotation can be more easily followed. The gears were created by the Geodesic program available on this site.