overdrive

A gear ratio higher than 1:1: one in which a single revolution of the driving element corresponds to more than one revolution of the driven element.

(figurative) A state of heightened activity.

(old-fashioned) A gear, on an automobile, higher than the traditional top gear, mainly to allow better fuel economy at highway speeds. In the 21st century, such gears are no longer viewed as "extra" and thus rarely called by this name.

(slang, euphemistic) Freewheeling (driving a vehicle with the transmission in neutral) on downhill stretches to achieve higher fuel economy and/or speed than otherwise. In colloquial registers, ethnically bigoted variants have been common, such as Jewish overdrive (alluding to the stereotype of miserly Jews) or Mexican overdrive or Polish overdrive (alluding to stereotypes of foolishness and poverty).

To drive too hard, or far, or beyond strength.