A50214 Bull Gear 450 33 spline Fits Case 450, 450B, 455BOne New Aftermarket Replacement Final Drive Bull Gear Fits Case (Fits Case IH) Crawler Dozers This aftermarket replacement final drive bull gear Fits Case 450, 450B, and 455B crawler dozers. The bull gear is a critical component of the final drive assembly, transmitting power from the drive train to the sprocket shaft. Each machine requires two bull gears one per side. Note: this 33 spline gear is identified with early Fits Case 450 applications;