Abstract
This paper will discuss the difference in transmission efficiency that result from steady-state versus transient testing. Historically, transmission efficiency testing has been performed in a steady-state mode as discrete torque and speed conditions. Steady-state testing was performed primarily because of test hardware and data acquisition limitations. Advances in dynamometer technology and controls have allowed the possibility of transient transmission testing. Consequently, standard dynamometer test procedures need to be updated to incorporate transient testing to more accurately report the dynamic effects within the transmission. These effects include torque converter blade deflection, converter ballooning, and clutch pack dynamics among others. Quantification of the main differences between steady-state and transient test results will be presented.