THIS INVESTIGATION EVALUATES THE PERFORMANCE OF CUBIC BORON NITRIDE (CBN) GROUND HYPOID GEARS USED IN HEAVY ON-HIGHWAY VEHICLE APPLICATIONS. THE TEST COMPARES GEAR SETS WITH VARIOUS PROCESSING COMBINATIONS INCLUDING AN EVALUATION OF LAPPING EFFECTS. DURABILITY PERFORMANCE WAS VERIFIED USING DYNAMOMETER TESTS. NOISE ANALYSIS WAS PERFORMED USING SOUND PRESSURE, SOUND POWER, AND SINGLE- FLANK MEASUREMENTS. A 100% BENDING LIFE INCREASE OVER CONVENTIONAL CUT AND LAPPED GEAR SETS WAS OBSERVED IN DYNAMOMETER TESTS OF CBN GROUND AND LAPPED HYPOID GEAR SETS. A SOUND POWER REDUCTION OF MORE THAN 150% WAS MEASURED FOR CBN GROUND AND LAPPED HYPOID GEAR SETS. NO DURABILITY PERFORMANCE BENEFITS WERE RECOGNIZED FOR UNLAPPED CBN GEAR SETS.