Why Can't the Automatic Transmission Shift Gears?
2 Answers
The reason why an automatic transmission can't shift gears is due to internal failure of the gear shift assembly. An automatic transmission does not require the driver to manually shift gears; the vehicle automatically selects the appropriate gear based on driving speed and traffic conditions. The gears of an automatic transmission are as follows: 1. P (Park) is the parking gear; 2. R (Reverse) is the reverse gear; 3. N (Neutral) is the neutral gear; 4. D (Drive) is the forward gear; 5. S (Sport) is the sport mode; 6. L (Low) is the low gear. The steps to start an automatic transmission vehicle are: 1. After sitting in the driver's seat, press the start button directly; 2. Depress the brake pedal and press the start button to ignite and start the engine; 3. Release the foot brake and let the engine warm up while stationary; 4. Depress the brake pedal again and shift to D (Drive) gear; 5. Release the handbrake and slowly release the foot brake to start moving.
I encountered this issue last time I was driving—the automatic transmission suddenly wouldn't shift, which was quite alarming. I first pulled over to check if it wasn't properly in the P position or if the brake wasn't fully depressed, as the safety system sometimes locks the gear to prevent movement. Low or dirty transmission fluid can also cause insufficient oil pressure, making it hard to shift, so I needed to open the cap to check the fluid's color and level. Another possibility is electronic component issues, such as a faulty control computer or sensor, requiring a scan with an onboard diagnostic tool for trouble codes. During that repair, it turned out to be a loose wire, and the mechanic fixed it quickly. It's important not to delay repairs, as neglecting the issue can damage internal transmission parts and increase repair costs. Regularly changing the transmission fluid can significantly reduce this risk—generally, every two years or 40,000 kilometers is sufficient.
