The testing technique outlined in this SAE Recommended practice was developed as part of an overall program for testing and evaluating fuel consumption of heavy-duty trucks and buses. The technique outlined in this document provides a general description of the type of equipment and facility which is necessary to determine the power consumption of these engine-driven components. It is recommended that the specific operating condition suggested throughout the test be carefully reviewed on the basis of actual data obtained on the specific vehicle operation. This document covers evaluation techniques for determining the power consumption characteristics of hydraulic pumps used on heavy-duty trucks and buses. The purpose of this document is to expand on the scope of the existing SAE J745. All of the specifications and apparatus utilized in that document for construction and industrial machinery can be utilized in this procedure. Information presented in the manner outlined as follows can be used to evaluate the hydraulic power requirements of fixed or variable-displacement pumps after the vehicle duty cycle has been determined.