The purpose of this paper is to discuss the results from a fault localization survey that was conducted using the Dual Gearbox Mechanical Diagnostic Test Bed. The test involved using two DC motors to drive and load two single reduction gear boxes coupled in series. An array of sensors including vibration, torque and temperature were used to.monitor each gearbox during a baseline and a seededhransitional gear fault test. The data was analyzed in order to evaluate the sensor types and locations and their ability to provide an indication and localization of a fault. The ultimate goal of this work is to find the least number of sensors that provide the greatest fault indication coverage for coupled mechanical systems.