What Is The Purpose of Overdrive?

If you’ve never heard of overdrive you may think it’s a way to increase the performance of your car by putting the car in overdrive mode.  While overdrive sounds like a way to boost the performance of your car, it’s really a way to save on fuel.

Overdrive is essentially a gear that is designed to keep your engine RPMs low to help save on gas.  While in overdrive gear torque will be decreased significantly, which is the main downside to driving in overdrive.

When Should You Use Overdrive?

Overdrive should be used when you are cruising on the highway at highway speeds to help you get better gas mileage and decrease the amount of fuel used on long trips.  Driving in overdrive gear keeps your engine RPMs low which will help you save on fuel in the long run. A lower engine RPM means that your engine doesn’t have to work as hard to keep your car moving forward which helps save on fuel.

When Shouldn’t You Use Overdrive?

While driving in overdrive can help you save money on gas there are some situations where you should not use your overdrive gear.  If you need to pass a semi or other slower-moving cars on the highway you should shift out of overdrive as in overdrive torque output is reduced which can make passing cars more difficult.

Do Manual Cars Have Overdrive?

Both manual and automatic cars can have an overdrive gear installed in them.  If you have an overdrive gear in your car the overdrive gear will be the last gear available.  So if you have a 6-speed transmission overdrive gear would be 6th gear.

Does Driving with Overdrive Off Save Gas?

No, driving with overdrive off or not in overdrive gear will actually use more gas because the engine will be spinning at higher RPMs.  The main purpose of overdrive gear is to decrease the engine speed to help save on fuel.

Does Turning Overdrive Off Make You Go Faster?

Yes, turning overdrive off or changing to another gear besides overdrive will allow the engine to spin faster and will create more torque.  Many people think that horsepower determines how fast a car can go. But really it’s torque that will move your car forward from a stop, which is why many trucks have higher torque ratings than horsepower ratings.

How Do I Use Overdrive?

In an automatic transmission-equipped vehicle usually, overdrive will be enabled when you start up the vehicle but can be disabled via a button labeled O/D or overdrive.

If your car or truck is equipped with a manual transmission then you have to select the overdrive gear manually.  The overdrive gear will be the last gear available if your car or truck has an overdrive gear.

What Is The Difference Between Drive and Overdrive?

The main difference between drive and overdrive is that drive is a term for drive mode in automatic cars while overdrive is a special gear designed to provide better gas mileage.  With manual transmissions, the overdrive gear needs to be selected manually. In automatic transmissions, the overdrive gear will be selected automatically as long as you don’t have overdrive disabled.

Should I Turn Off Overdrive When Towing?

If you are going to be towing or carrying heavy payloads it’s best to disable overdrive mode.  While in overdrive the vehicle will have reduced torque output which is the opposite of what you want when you are towing or carrying heavy payloads.  Torque is essential to getting your vehicle moving from a standstill, without torque your truck or car wouldn’t move at all.

Can Overdrive Mess Up Your Transmission?

While driving in overdrive can help save on gas there are some scenarios where overdrive should not be used.  You can cause damage to your car’s transmission in a manual car if you drive in overdrive gear when you shouldn’t.    If you have an automatic transmission your transmission will pick your gears for you which means you don’t need to worry about damaging your transmission by picking the wrong gear.

In a manual car, you want to be careful not to lug your transmission which means you are in the right gear based on the speed at which you are currently traveling.  When you are just getting started moving you would want to be in first gear. As you pick up speed you would want to shift through the gears until you get to get to the gear that is right for the speed you are traveling on the road.

This means that if you slow down or come to a stop you then need to downshift, otherwise your transmission will jerk trying to move your car with a reduced gearing ratio (and reduced torque).  If you slow down and need to pick up speed again you would want to shift out of overdrive to pick up speed again otherwise you risk lugging your transmission.

While lugging your engine and transmission once or twice likely won’t cause issues with your transmission, doing so a lot can damage your drivetrain and cause increased wear to your clutch.

Related Questions

Can you shift from D to 2 while driving?  Shifting from D to 2 while driving is ok provided you aren’t traveling at high speed.  When you shift out of drive (D) and into second gear (2 on your gear selector) you are forcing your automatic transmission to shift to second gear.

If you try to shift into second gear at high speeds it will raise your engine RPMs and potentially blow up your engine. Shifting from D to 2 from a stop allows you to manually select second gear, shifting from 2 to 3 (if 3 is an option) will allow you to manually select third gear in an automatic transmission equipped car.

Is it Bad to Shift into Neutral While Driving A Manual Transmission?  No, shifting to neutral while driving a manual transmission will not hurt the transmission at all.  There is a term called double clutching shifting where you would push in the clutch to move to another gear and then release the clutch while still in neutral.

Then when you are ready to move to the desired gear you would push in the clutch again, shift into the desired gear and then let out the clutch.

Double-clutch shifting used to be required on a lot of older cars and semis but on most modern cars is not required.  As you can imagine using the double clutch shifting method would increase the amount of time in between shifts which is the opposite of what you want.  You want to be able to switch between gears as fast as possible without the least amount of delay between shifts.