What does overdrive do on a 2004 Chevy Malibu?

In a 2004 Chevy Malibu, overdrive is a gear in the automatic transmission that allows the engine to run at a lower RPM at higher speeds. Essentially, it's a taller gear ratio than the other gears.

When overdrive is ON, the transmission uses a higher gear ratio, resulting in:

* Better fuel economy: The engine doesn't have to work as hard at highway speeds.

* Quieter operation: Lower engine RPM means less engine noise.

When overdrive is OFF, the transmission will not use the overdrive gear. This is useful in situations where:

* More engine braking is needed: Going down steep hills.

* More power is needed for passing or towing: The lower gear allows for quicker acceleration.

* You're driving in rough terrain: Avoiding the overdrive gear can prevent the transmission from hunting between gears.

The overdrive button (often labeled "OD OFF" or similar) overrides the automatic selection of the overdrive gear, forcing the transmission to use a lower gear. The transmission will still shift through the other gears normally.