Commercial Heavy-Duty Power Transmission Fluids

The performance features of seven types of commercially used power transmission fluids are compared using test methods as required by the equipment manufacturers' specifications. These fluids fall within the SAE 10-20 viscosity grades and are used in the transmission, the hydraulic system, and, in some cases, the final drive. The significance of the various performance tests is also discussed. The overall data indicate that some fluids can be combined into one to simplify oil supply problems inherent to mixed fleet operations. However, the continued need for specialty fluids is also apparent.