* High engine RPMs: Driving at high speeds in low gears forces the engine to rev very high. This generates excessive heat and puts significant strain on the engine, transmission, and other components. This can lead to premature wear and tear, and potentially catastrophic engine failure.
* Reduced Fuel Efficiency: High RPMs in low gears are incredibly inefficient in terms of fuel consumption. You'll burn far more gas than if you were driving at the same speed in a higher gear.
* Transmission Damage: Automatic transmissions are designed to shift gears based on speed and engine load. Forcing the transmission to operate at high RPMs in a low gear for extended periods stresses the transmission components and can lead to damage.
* Harsh Driving Experience: The car will likely feel rough and jerky, making for an unpleasant and potentially unsafe driving experience.
In short, always allow your automatic transmission to shift up to the appropriate gear for the speed you're traveling. This is the most efficient and safest way to drive.
