When do I use the od button on 2003 Ford Ranger?

The "OD" button on a 2003 Ford Ranger is used to control the overdrive feature of the transmission. When the button is engaged (OD on), the vehicle can shift into higher gears for better fuel efficiency at highway speeds. If you’re towing a heavy load or driving in hilly terrain, you may want to turn off overdrive (OD off) to provide more power and control. To use it, simply press the button on the gear shift lever as needed.