IN THIS CHAPTER WE PRESENT TECHNOLOGY relating to hydraulic and transmission fluids. Under the topic of hydraulic fluids, we describe fluids both for tractor-type equipment and industrial hydraulics. We list the performance requirements of various equipment manufacturers and teach the formulating of an appropriate fluid. Under the topic of transmission fluids, we describe fluid requirements for automatic transmissions, power transmissions, and continuously variable transmissions. We conclude the chapter by citing formulation examples for each type of fluid.