Can S gear and D gear be switched freely?
2 Answers
Automobile S gear and D gear can be switched freely, but safety precautions should be taken. Relevant information is as follows: Transmission aspect: Lower gears allow the transmission to output greater torque (power). When switching to S gear while driving and accelerating, the computer will immediately control downshifting to obtain greater torque output. Engine aspect: Generally, for naturally aspirated engines, the maximum torque occurs around 4000 rpm. Delaying the shift point allows the engine to always operate within the maximum torque speed range, similar to what is seen in racing movies where drivers don't release the throttle during shifts to prevent engine speed from dropping, thus avoiding the need for a speed climb after shifting. Long-term use of S gear: The powerful performance of S gear comes at the cost of significantly increased fuel consumption. Prolonged use of S gear can also lead to accelerated wear of the engine and transmission, reducing their service life. Therefore, it is not recommended to use S gear for extended periods.
I've been driving automatic transmission cars for over a decade, and I can responsibly tell you that you can indeed switch between S mode and D mode while driving without needing to brake or come to a complete stop. Last time when I was in a hurry on the highway, I directly shifted from D to S for overtaking, and the engine RPM immediately surged with a strong kickback sensation. However, you need to pay attention to speed changes, especially when using S mode for engine braking downhill—just avoid shifting during sharp turns. For daily commuting, D mode saves fuel, while I prefer using S mode to maintain higher RPMs when climbing mountain roads. Although the transmission isn't that delicate, I still avoid shifting when the throttle is fully pressed to minimize impact on the gear set. The veteran driver's advice is to switch as needed without overdoing it.
