The established procedure for assessing automatic transmission fluid level often necessitates that the engine is actively operating. This practice ensures an accurate reading of the fluid level within the system. This method contrasts with checking engine oil, which is typically performed when the engine is off, allowing oil to settle in the pan for a stable measurement.
Operating the engine engages the transmission pump, circulating the fluid throughout the system, including the torque converter. This circulation simulates operational conditions and allows the fluid to reach its optimal operating temperature. Checking the fluid level under these conditions provides a more representative indication of the fluid’s volume during typical vehicle use. This practice is crucial because fluid levels can vary significantly depending on temperature and distribution within the transmission.