To keep up with our series of driving mode articles, today we at Automilas.com would like to drive you through what you need to know about Overdrive gear in automatic transmission car.

What the Overdrive Gear does

The Overdrive gear, OD, works to force the RPM down at a certain speed, consequently improving the speed as well as the fuel economy. Besides, OD supports the car in providing the optimum performance while cruising at higher speeds.

OD works to force the RPM down, consequently, enhances the speed as well as the fuel economy

When you should use Overdrive

Commonly, overdrive gear is activated by a dedicated button on the gearshift. Switching it on means LOCKING IT OUT,  not applying it. When the OD is pressed, the transmission goes through all the gears and limits functions of other gears. To put it another way, the vehicle will downshift from the highest gear if you activate OD while traveling at high speed.

In normal drives, you should always lock the OD (again, to switch it on), thereby leaving the car shift to the top gear all automatically when necessary. However, overdrive gear can improve the performance of the car in certain situations, which are elaborated below.

When you are picking speed

When your car running at high speeds (above 60 miles per hour for new cars, and 50 mph for older ones), your engine is put under more strain with the RPM elevates. Activating the OD will effectively reduce pressure and at the same time bring down the RPM.

Note: OD should not be on in city drives where the speed is inconsistent or when you are at speeds lower than 50 mph.

When you need to downshift

The engine and the braking system are put under much stress when you are stuck in heavy traffic or going downhill. In traffic jams you constantly make sudden pressing on the pedal and speed the car, and you exert continuous pressure on the brake pedal while going down an inclined terrain. In such situations, the overdrive gear helps maintain the RPM above idle and make sure the engine and the brake won’t be strained.

The Overdrive gear helps maintain the RPM

Video: Overdrive On/Off Differences