This paper describes validation testing of a comprehensive vehicle corrosion simulation and modeling tool under development by US Army TARDEC called “ACES” (Accelerated Corrosion Expert Simulator). ACES is used to predict the initiation and growth of corrosion on Wheeled Vehicles, Aircraft, Ships and other Assets. It is able to simulate coating & corrosion performance under various operating scenarios and to forecast & display deterioration of vehicle systems over time. ACES has a high degree of correlation to Accelerated Corrosion Deterioration Road Test (ACDRT) data and the original prediction algorithms were correlated using ACDRT data from the Army Family of Medium Tactical Vehicles (FMTV) truck. This paper describes validation testing of the predictions conducted by a third-party stakeholder using a different vehicle, namely the Marine Corps’ Medium Tactical Vehicle Replacement (MTVR).