Abstract: Method for recording loaded running tooth contact patterns on navy or marine large reduction gears comprising the steps of providing a pair of meshing gears having transversely spaced teeth with surfaces subject to wear, coating the surfaces of as least one gear with a substance providing visual indication of tooth wear, running the gears under load, providing a platform adapted to move along the teeth and adapted to support and guide a video imaging probe, moving the platform along selected teeth while directing the probe at the contact surface of a transversely spaced "observed" tooth, and recording a video image of the observed tooth surface. The method further includes synchronizing the video image with the video image of an identification marker temporarily disposed adjacent to the observed tooth and synchronizing the video image with an audio record describing the tooth contact location and pattern.