Driving at a very low engine speed in a high gear places massive mechanical stress on the rotating assembly. When the driver applies heavy throttle under these conditions, the engine struggles to accelerate, often shuddering and producing a deep, booming resonance. This practice creates severe cylinder pressures that can cause low-speed pre-ignition and destroy connecting rod bearings.
Don't lug it up the hill in fifth gear, drop down to third and let the engine rev.
Related terms
Downshift
The act of selecting a lower gear in a transmission to increase engine speed and torque.
Redline
To operate an engine at its maximum safe rotational speed.
Gear change
The mechanical act of shifting a vehicle transmission from one ratio to another.
Knock
An abnormal and damaging combustion event where the air-fuel mixture self-ignites prematurely.