so what exactly is overdrive and does turning it off make you any faster

 

basically with overdrive on the engine speed decreases which reduces the amount of fuel being used and also helps keep the engine healthy. Taking overdrive off will do the exact opposite.. you would use more fuel and create more wear on the engine. As in making the car faster I would say no but just making a guess i just don't see how it would do anything.

 

Overdrive is your highest gear, used for gas mileage on the highway and such. In an auto, it is likely 4th, with a manual, it would be either 5th and/or 6th. You should leave it on in most cases. If you are driving in a very hilly area, such as in the mountains, you might consider turning it off to keep the car from shifting in and out of it so much. You might also disable it for rolling starts or whatever (not that you should be street racing). If you disable it, the car might only have to downshift 1 gear whereas in overdrive, it might have to downshift 2 gears.

I am no expert on automatic transmissions, but that is the best of my understanding. Specifically to your question, it won't make you faster per se, but it would help accelerate faster because of the downshift issue I described above. Is that necessary for everyday driving, no. Will it use up more gas, yes. Don't disable it unless the situation actually calls for it.

Scott

 

it does what above was said. all it does when 'off' is let the car go between gears 1,2,3. with it on it lets the car go into gears 1,2,3,4. so no it will not make you faster, it will just hurt your gas milage.

 

why do we even have it its useless

 

because i think, not 100% that when racing at the drag strip, it is bad to go WOT into 4th, not sure....but it is their for the same reason a standard has 5th, gas milage.

 

True, going into 4th at WOT is damaging to the transmission.

Wikepedia has a good explaination of overdrive and why it's there.

http://en.wikipedia.org/wiki/Overdrive_(mechanics)

 

Becuase when you drive in the mountains it lets you lock out 4th gear in your cars whihc keeps the tranny from "hunting" between 3rd and 4th gear which makes it hot. Its also the reason you cna select only 1st & 2nd its really for the mountains not for racing.

So in short the reason you can turn off d/d and or select other gears is because it lets you make the car not hunt for gears which makes it run very hot and is is very very bad for your tranny.

 

i dont use it. I just thought it was kinda useless if i didnt use it and im not in the MT's much so ill prob nver use it.