Regarding the filling level of an automatic transmission, what can occur if it is overfilled?

When an automatic transmission is overfilled with fluid, it can lead to a condition where excess fluid is forced out of the transmission case. This typically occurs because the fluid needs space to expand and move within the transmission while it's operating. If there is too much fluid, it can cause excess pressure, prompting it to leak from seals and gaskets.

This leakage can manifest in various ways, including puddles under the vehicle, and it can also lead to a decrease in fluid levels over time, potentially causing the transmission to operate under low fluid conditions if not corrected. Addressing overfilling is important to maintain proper transmission function and avoid additional mechanical issues related to fluid loss and potential damage to the transmission components.

The other options—reducing fluid pressures, shortening the lifespan of the fluid, or improving shifting quality—are generally not accurate consequences of overfilling. In fact, while overfilled fluid can potentially cause erratic shifting or damage due to aeration of the fluid, the most immediate and observable issue tends to be the leaking of excess fluid.