The automotive term for an automatic transmission that downshifts when the accelerator is floored for extra power is kickdown.
A kickdown lowers the selected gear ratio, raising engine speed and placing the engine closer to its stronger power range. The result is sharper acceleration, useful for overtaking, merging, or climbing a hill. In older transmissions, a switch or cable beneath the accelerator could trigger the action; modern systems normally detect throttle position electronically.
Kickdown does not mean redline shift, which refers to shifting near the engine’s maximum safe speed. It is also different from overdrive, the higher-ratio gearing used to reduce engine speed during cruising. Stall speed concerns the operating speed of a torque converter when its output is held stationary.
A transmission may skip more than one gear during kickdown, depending on road speed, throttle position, programming, and engine load. Some newer cars also combine automatic kickdown logic with selectable sport or manual modes, but the basic purpose remains the same: trade economy and quiet cruising for immediate pulling power.