Abstract: A pair of gears, which form a gear set, are tested by mounting the gears on parallel axis spindles which are located at a fixed center distance. One of the parallel axis spindles is contained in a spindle housing that is rigidly mounted to a massive base. The other gear of the set is contained in a spindle housing which is supported on top of a pair of parallel leaf springs that are connected to the base. The spindle in the spindle housing that is rigidly mounted on the base carries a pulley at its end that is remote from the gear set which is coupled through a drive belt and a second pulley to a drive motor. The spindle in the resiliently mounted spindle housing on the leaf springs is coupled to an eddy current brake at its end which is remote from the gear set. An accelerometer, which is coupled to a conventional electronic output indicator, is mounted on the resiliently mounted spindle to provide indications of the vibrations caused by the gear sets.