"overdrive" button

[twiist]

My car has this button that activates/deactivates "overdrive mode." Can anyone explain to me in girl-friendly not-mechanic terms what that is? 

Hinanap ko kasi sa google, sabi something to do with the gears that the car uses to drive. Pero ano ba kasi yung epekto ng "high gears" and "low gears" sa driving?

[dm1179]

ano car gamit mo? i assume it has automatic transmission (A/T).

Overdrive button tells the car what gear range it can use. example, for a 4-speed A/T car, you have gear 1, 2, 3, and 4. with Overdrive ON, you are telling the car that it can use all 4 gears, i.e. 1, 2, 3, 4. with Overdrive OFF, you are telling the car that it can use 3 gears only, i.e. 1, 2, and 3.

low gears = 1, 2 = used to start movement of car, engine braking, uphill climbing, slow speed
high gears = 3, 4 = used for high speed, provide better fuel economy

you should always drive with Overdrive ON for better fuel economy. this is also discussed in your vehicle owner's manual.

[twiist]

Thanks for explaining, dm1179!

Unfortunately, I don't have a copy of my car manual since it's just a secondhand car that my dad bought and allowed me to use (jobless student pa me hahahaha) and he can't remember where he put the manual anymore.

That's a good idea though, I should look for a manual online.