How do you analyze and reduce gear whine in a transmission?

Gear whine analysis involves: Order tracking to identify gear mesh frequencies, measuring transmission error through single-flank testing, analyzing gear micro-geometry (profile, lead, crowning), evaluating housing structural dynamics and radiation efficiency, and identifying excitation sources versus response amplification. Reduction strategies include micro-geometry optimization to minimize transmission error (<2 micron for quiet operation), profile modifications (tip relief, root relief), surface finish improvement, gear blank stiffness optimization, housing design for structural damping and vibration isolation, and bearing preload optimization. Simulation uses FEA for gear contact stress and system-level NVH models.