Noise and vibration are undesirable side effects associated with the use of spur gears in drivetrains. With market pressures for higher power densities, the development of high performance drivetrains with reduced noise and vibration thresholds forms a generic problem in the power transmission and gearing fields. In this paper, a process to reduce mesh stiffness variation in a spur gear set through the use of Differential Crowning™ technology, with concomitant reductions in acoustic noise and structure borne vibration, is presented. Through certain topological modifications to the profile of the gear teeth, mesh stiffness variation can be consistently minimized over a range of input loads. Analytical predictions for the mesh stiffness variation and transmission error in a conventional baseline drivetrain, and in one optimized through Differential Crowning™, are discussed. Design and operating parameters are used as inputs in a “design of experiments test protocol” so as to isolate those parameters which most influence performance. Controlled testing is performed in an acoustically-treated chamber, and sound pressure, sound intensity, vibration, and transmission error data are obtained for the baseline and optimized drivetrains. The test results are correlated with the predictions, and they demonstrate a mean reduction of 8 dB in total sound power for the optimized drivetrain over the six input speeds and loads that were considered.