Final answer:
The correct verification during the reinstallation of a multi-piece driveshaft after replacing a universal joint is driveshaft phasing, ensuring alignment of the yokes and proper power transmission.
Step-by-step explanation:
When replacing a universal joint in a multi-piece driveshaft, it is essential to verify driveshaft phasing during shaft reinstallation. Driveshaft phasing refers to the alignment of the yokes on each end of the driveshaft sections. Proper phasing ensures that the angles are concurrent, which allows for smooth power transmission and reduces vibrations that could lead to premature wear or damage. Inaccurate phasing can result in an imbalanced driveshaft and increased strain on the components.