* Engine braking on downhill grades: Lower gears provide more engine braking, helping control speed and reducing brake wear.
* Increased power for passing or towing: Disabling overdrive keeps the engine in a higher RPM range, providing more power.
* Better control at lower speeds: Useful in situations like driving in mud or snow.
When the overdrive is off, a light usually illuminates on the instrument panel indicating that it's deactivated.