Global vehicle emissions reduction initiatives have warranted the development and usage of new materials and processes not traditionally used in the automotive industry besides exclusive applications. To support this mandate, vehicle lightweighting via metal replacement and design optimization has come into sharp focus as a doubly rewarding effect; namely, a lighter vehicle system not only requires less road load power for motivation, but also allows for smaller, usually more efficient powertrain options, which tend to be more efficient still. The automotive industry has begun to embrace adapting composite materials that have typically been available only to the upper end of the market and specialty racing applications. The specific component detailed in this paper highlights the challenges and rewards for metal replacement with an injection molded, fiber reinforced plastic for usage in mass produced drivetrain systems, namely the Electronic Limited Slip Differential (eLSD).The component detailed in this paper is a mechanical plenum that serves as a hydraulic supply, a fluid pressure control and a structural body for an eLSD system. Not only does the design approach for the component qualify for weight savings through material comparison, but its processing also allows for sub-component integration, further reducing final assembly complexity and lowering production cost. Material and production tooling costs are also favorable due to the net-shape processing allowed via injection molding.The injection molded design replaces a previously permanent molded aluminum with an injection molded, short glass fiber reinforced polymer. The paper describes the challenges and advantages of design and processing that have allowed the plenum to be optimized for the lightweighting of the eLSD system. A general design approach encompassing the myriad activities necessary for a transition from metal to plastic will be discussed also highlighting the lessons learned during the process of readying the component for the transition from research and development prototype into production acceptance.