Putting a car into neutral going down a long hill because your top gear is not high enough to prevent over-revving or because your injectors do not shut off under deceleration
The racers in the Carrera Panamerica in Mexico discovered their cars would go faster rolling down the long mountain grades in Mexican Overdrive than in gear.
by vactrac November 13, 2010
Taking an automobile out of gear or shifting into neutral while on a decline in an effort to improve fuel economy.
After cresting the top of the hill, Juan shifted his pick-up into Mexican overdrive.
by keefer March 03, 2004