What sign might suggest that a vehicle's transmission is failing?

A grinding noise during shifting is a significant indicator of potential transmission failure. This sound typically suggests that the gears within the transmission are not engaging properly or that there might be wear and tear on the components responsible for shifting gears. When a vehicle's transmission is functioning correctly, gear changes should be smooth and quiet. If grinding noises are present, it might indicate issues such as low transmission fluid, worn-out gears, or problems with the clutch in manual transmissions, all of which can lead to serious transmission problems if not addressed.

The other options present signs that may indicate different types of mechanical or system failures. For instance, fluctuating temperature gauges might suggest engine cooling issues rather than transmission problems. Engine stalling could indicate fuel delivery or ignition system issues, while noise from the steering wheel typically points to problems with the steering system or power steering components. Thus, the grinding noise specifically relates to issues that are directly linked to the functioning of the transmission system.