After years of successful reliable applications@ a component failure on a new application cannot be explained with static stress analyses@ modal failure analysesmay be required. Finite element modal analyseswas used to identify the mode and its frequency that cause a high range gear and drive ring assembly to fail prematurely. ACampbellDiagram was used to identifymodes in the operating range of a six--speed transmission that could cause the drive ring to fail. Redesigning the assembly to move the criticalmodes out of the operating range is described.