This gear set consists of an input shaft and a two-gear cluster that transmits torque from the engine to the gearbox countershaft. The shaft carries the drive gear, and the cluster engages with the mating gear on the output side to establish the selected speed ratio. Wear on the gear teeth produces a whine or rattle under load, and a worn shaft bearing allows radial play that misaligns the tooth contact pattern. The manufacturer machines the gear profiles to match the original tooth form and helix angle, which maintains the factory backlash specification without requiring shimming. On reinstallation, verify that the shaft pilot aligns with the bearing bore and that the retaining nut is torqued to specification.