For decades automotive manufacturers have looked upon metals for use throughout the automobile. Since the time of Henry Ford's Model-T, metals have been used throughout the manufacturing process for their durability and strength. This “metallic mentality” has been challenged in recent years with some success in interior parts and body components. But underhood applications, such as, engine and transmission components have remained primarily in metals with the exception of some thermosets.Until recently, very few thermoplastics have been able to offer the essential, combination of physical and mechanical properties needed for successful replacement of metal parts in powertrain components. Ryton PPS is a high temperature thermoplastic which offers this combination of properties that is needed in such applications.This paper will discuss the advantages of using PPS in powertrain applications. It will also show that with proper design many metallic powertrain components can be converted with substantial weight and cost savings. Several appropriate part applications will be discussed. Finally, one of the amazing properties of PPS is that of its affinity for different filler systems. Thus, PPS can be customized through compound engineering to rival various properties of metals. Two examples of these creative formulations are being introduced. The combination of these subjects should add merit to new and economic means of manufacturing traditional powertrain. components with PPS engineering thermoplastic materials.There are world wide trends in industry today to convert from expensive, heavy, labor intensive metal construction to efficient, cost effective, structural plastics. One of the highest performance plastics being used in this move is Polyphenylene Sulfide.Plastics Design Forum magazine conducted a survey of 300 design engineers and questioned them regarding the major reasons plastic usage will increase in their industries.* The percentage of responses fell in these major categories:Weight reduction - typically plastics are 1/2 to 1/4 the weight of their metal counterparts.Cost effectiveness - savings in manufacturing and energy costs are 20% - 40% with plastics.Durability/Corrosion Resistance - plastics have excellent corrosion resistance, much higher lubricity and tighter tolerances which resist in-service failure. PPS has superior resistance to a wide variety of chemical environments, even at elevated temperatures.Ease of processing - plastics have much lower energy requirements with most fabricating processes.Low scrap rates and recycleability - PPS thermoplastics are completely reprocessable often eliminating scrap, while producing finished parts in a single molding operation.High temperature resistance - PPS is one of few plastics which have a heat distortion temperature of over 260° C (500° F) and a UL Continuous Use Temperature Index of 200° C - 240° C (392° F -464° F).This paper presents the advantages of using PPS thermoplastics in traditionally metallic underhood components. Several examples are used to support this process.