Shifting gears means changing gears, and its function is to adjust the speed of the vehicle. Driving at a low speed in a high gear will cause the engine to stall, while driving at a high speed in a low gear will damage the engine. It allows the car to drive at a very low and stable speed, which is difficult to achieve with the engine's minimum stable speed alone. The reverse gear in the transmission enables the car to move backward, and the neutral gear allows the engine to be separated from the drivetrain for extended periods during engine start-up, parking, and coasting. When starting, you shift into gear. When the tachometer needle reaches around 2000 RPM, you can shift to 2nd gear. Then, when the tachometer reaches around 2000 RPM again, shift to 3rd gear. Next, check the speedometer—when it points to around 40 mph, shift to 4th gear. At this point, the car can drive for a while. Then, when the speedometer needle points to around 60 mph, shift to the highest gear, 5th gear. This driving and shifting technique ensures the car operates normally and generally avoids insufficient power. An automatic transmission does not require the driver to shift gears manually. The vehicle automatically selects the appropriate gear based on driving speed and traffic conditions. Typical automatic transmission vehicles have gear positions like P, R, N, D, 3, 2, and 1. A manual transmission requires the driver to manually move the gear lever to change the gear engagement inside the transmission, altering the gear ratio to achieve speed changes. Manual transmission vehicles have gear positions like 1, 2, 3, 4, 5, N, and R.
