A method using discrete design optimization to maximize product reliability and customer satisfaction through uniquely partitioning system architecture is developed and presented in this paper. Using integer programming, constraints such as cost, weight and physical volume are incorporated into a mathematical model to improve system reliability through the introduction of system architectural redundancies. An advanced automatic transmission electronic shift control system is examined as a potential application for the aforementioned methodology. A significant improvement in system reliability is achieved through the application of this optimization tool in the shift control design problem. A generic model is proposed for architectural optimization of emerging advanced technology systems with requisite critical reliability requirements.