During the differential plug inspection, what should be observed?

During the differential plug inspection, the primary focus is on the integrity of the differential housing and ensuring that it is sealed properly. Observing that there are no leaks indicates that the differential is functioning correctly and there are no issues with the lubricating fluids. A leak could mean that fluid is escaping, which can cause overheating, damage to the differential, or inadequate lubrication of the gears inside. Therefore, confirming the absence of leaks is critical for the safe and efficient operation of the vehicle. This ensures that the differential has the necessary lubrication to operate without risk of failure.

Other options touch on issues like the driver's safety or the condition of the plug itself, but they do not directly address the essential function of the inspection related to the differential plug's role in maintaining fluid containment.