Many analyses of gear rattle caused by drive line resonance have been reported. The fewer number of cases can be observed with analysis of drive-rattle in comparison with that of gear train idling-rattle. This paper introduces the method of evaluating drive-rattle objectively. And this paper introduces the method of specifying gears, which have the large contribution rate to drive-rattle, at a single measurement attempt with a vehicle. This method analyzes the relationship between gear vibration and transmission case vibration. In addition, nonlinear drive-rattle simulation has been developed with consideration given to gear backlash. Therefore, more systematic drive-rattle analysis has become possible.