The noise, vibration, and harshness (NVH) performance of electric vehicles (EVs) significantly impacts comfort, safety, and reliability. Unlike traditional internal combustion engines, EVs, powered by electric motors, operate more quietly due to the absence of engine noise. However, this serene environment can amplify other sources of noise, such as waviness in bearings or shafts. In this study, a tonal noise associated with gearbox shaft waviness is investigated. Despite the small amplitude of the problematic shaft waviness (around 1 μm), it affects bearing raceway geometry due to interference fit. Test results reveal that the shaft waviness transfers to the bearing inner ring raceway. When assembled with the problematic shaft, the bearing inner ring exhibits the same order of waviness. No waviness is observed when the ring is disassembled. Initially attributed to inner ring waviness, the abnormal noise originates from the shaft itself. This research shows the intricate relationship between shaft waviness, bearing geometry, and NVH performance in EV motors. Understanding these factors is key for optimizing motor design and ensuring a quieter, more comfortable driving experience.