<div class="section abstract"><div class="htmlview paragraph">THIS PAPER deals with hydrodynamic split torque transmissions.</div><div class="htmlview paragraph">The first part is a mathematical investigation of systems with two parallel power paths of the power-dividing and power-uniting type. The basic equations for split torque transmissions as well as for engine-transmission packages are discussed. General criteria for the usefulness of split torque transmissions are presented.</div><div class="htmlview paragraph">The authors also investigate actual performance characteristics of various split torque transmissions. The overall effect of the engine transmission package on engine speed, output horsepower, output torque, and overall efficiency is analyzed and discussed.<span class="xref">*</span></div></div>