What Causes an Automatic Transmission Car to Suddenly Shift Gears While Driving?

[BeckettRose]

Automatic transmission cars may suddenly shift gears while driving because the driver did not fully engage the gear shift. Solution: Simply re-engage the gear shift. Introduction to Automatic Transmission Gears: The gear positions on an automatic transmission car, from top to bottom, are P (Park), R (Reverse), N (Neutral), D (Drive), S (Sport), and L (Low). Generally, cars with automatic transmissions adjust speed via the transmission control system, which automatically selects the appropriate gear based on engine speed and load, replacing the driver's subjective judgment of timing and gear shifting. Important Notes: For general driving needs, using only the P (Park), R (Reverse), N (Neutral), and D (Drive) gears is sufficient. However, in certain special driving conditions, other functional gears may be required.