A program to experimentally and theoretically study fundamentalmechanisms of gear dynamic behavior is being conducted at the NASA Lewis Research Center in supportof a joint research program between NASA and the U. S. Army. This paper presents theresults ofdynamic tooth-fillet straingage measurementsfrom theNASA gear-noise rig, and it inlroduces a technique for using these measurementsto separate thenormaland tangential(friction) components
of the load at the tooth contact.