Due to recent technological advances, preciseness in gear transmission has evolved into an essential goal, in which vibration is one of the critical issues. This study demonstrated an experimental platform for a proposed construction model on the spur gear pair, in which damping particles were filled into six through-cavities in gear bodies to verify decreases in vibration. The experimental design involved variable control of input rotational speed, filling ratio, particle size, and material to investigate the damping particles’ behavior. Subsequently, operating both ADAMS and EDEM software established a reliable two-way coupling analysis model. The results confirmed that the filling damping particles effectively reduced system vibration, and both simulation and experimental tests demonstrated a consistent impact. In addition, the damping particle behavior indicated that high rotational speed was more effective in vibration reduction, and increased filling ratio decreased radial vibration. Increases in particle diameter only contributed slightly to vibration reduction. Moreover, although density increase significantly reduced vibration, bead elasticity did not impact vibration. Finally, the dynamic behavior of damping particles with the greatest reduction impact was achieved by applying a soft lead bead in a 5-mm diameter, 48% filling ratio, and the system working at a rotational speed of 600 rpm.