[sooks]

What does the over drive do and when should i turn it off/on?

[JayMina121]

omg...you don't know what overdrive is? it's like 5th gear man...use it like above 50ish mph and for cruising on freeways and junk...not up hills or not for accelerating or anything like that. just for saving gas mileage above 50ish mph. is this your first car or something?

[sooks]

lol no this isn't my first car. i've never used it before. but on the scion xb it automatically turns on overdrive when the car starts?

[DTRAIN619]

The O/D button is your 4th gear in the automatic, and is is always "on" unless you turn it off. In most cases, you should just leave it on, as it keeps the engine noise down (3rd gear RPM's vs 4th gear RPM's) and helps with the gas mileage.

However, if you find the tranny "hunting" for gears (like on a long incline), that's a good time to turn it off (so it doesn't keep downshifting).

Hope that helps.

[bB626]

Originally Posted by JayMina121

is this your first car or something?

well, my first car was an '89 Tercel and it didnt have OD in it. so yeah...what Dion said.

[sid]

hmm, I thought you use it when you drive over something?......


















okay, bad joke,... carry on!!!

[toaster_pilot]

ahahahahahaha

[bB626]

LOL!!!! thats funny Sid!

[gerashell24]

lol.i thought u were serious for a sec.

[Staticlink05]

wow intresting i had that same question... lol thanks

[510bre]

overdrive refers to the gear ratio being over the 1.0 its prolly like .93 or something. its basiclly like a 5th gear in a five speed or 6th in a 6 speed. the motor doesnt have to turn as fast to spin the tranny thus using less gas.

[Todd2die4]

i dont it until i go over 40 mph, keeps the revs lower then turn it on over 40 to keep the revs low

[xbgurlbzzz]

ok so dumb question... you can just turn it on in the middle of driving down the road? I am going on a trip this weekend and thinking this might help to save some gas?? So when I get over 40-50 mph just turn it on?

[PCH]

If it doesn't say "OD OFF" on your dash, the overdrive will engage automatically when you reach certain speed. It's safe to hit the button while driving, the engine will rev higher and produce more power (and use more gas)
Just play with the button few times- you'll understand how it works.

[Calesta]

I don't feel like people are explaining it properly...

How to Use the Overdrive Button on a Toyota | eHow.com

The overdrive button basically enables or disables your highest/tallest gear in an automatic transmission. EVERY transmission in modern cars has at least one overdrive gear. The OD gear set is the one that has a ratio lower than 1.0:1, meaning that the engine output is being slowed down before it reaches the next stage in the driveline.

Engine -> primary gear ratio -> final gear ratio

In overdrive, the engine's torque has significantly LESS mechanical advantage over the car since it is no longer going through a continuous gear reduction all the way through the transmission to the wheels. The overdrive gears the torque UP, then back down again when it hits the final drive.

Hitting the OD button to turn the overdrive OFF basically locks out the tallest gear in the car. This really doesn't do a single thing for you until you hit cruising speed. If you have your foot on the floor getting onto the freeway, the transmission is going to be in the lowest/shortest gear possible to give you maximum torque to accelerate the car. Once you get up to cruising speed, that's where the OD OFF button will make a difference. Instead of being in 4th gear (on a 1st gen), you'll be topped out in 3rd gear. All you basically gain is avoiding the wait to drop into 3rd or 2nd gear when you mash the gas. See why it's pointless? You just burn more gas on level ground.

Where it IS helpful is if you're going uphill and don't quite have enough torque in 4th to pull you along and you want to keep the transmission from hunting back and forth between 3rd and 4th gear while driving, or if you're slowing down and want to use a bit more engine braking (not like you get much in an auto) on the highway when you get off the gas.

Unless you're trying to keep the transmission from hunting between gears, just leave the overdrive on. There's no difference once you mash the gas and it downshifts anyway.

[PCH]

That's a pretty good explanation but let me add something from my personal experience. I rarely floor the gas pedal because there is really not much difference in engine power output between throttle open 75% and 100%. So i hit the OD when i want to accelerate when it really counts (like freeway merging or passing) without loosing time because of the delay in shifting out of the overdrive automatically. When i know i'm about to start passing somebody i'll switch OD off and only after that i give it more gas- the responce from the engine is very quick. The automatic gear changing on the xB is fairly good but there is always a slight delay and possibility of it shifting back and forth (hunting).
I usually leave the button alone, but when i want to have a little more fun driving, i hit it, especially since i wired it to my steering wheel and it's right on my fingertips

[gravebox]

OD is a function that is used to improve mileage while cruising at a continuous speed.

older vehicles use to give you the option of being in a "non" over drive setting. some people speculated that it would be harmful to the car to keep it in over drive all the time, this is incorrect. over drive is just the ECU's way of automatically going into a lower gear so that you're not running higher rpm's than what's needed to keep the vehicle moving. if you want more speed, simply put more throttle down and the ECU will automatically down shift to the necessary gear to accelerate and once at that speed and you start keeping it continuous then it will automatically up shift to a lower gear to consume less fuel.

over drive is just the automatic ability to change into the next lowest gear to consume less fuel. having over drive on all the time does nothing to your car at all that is harmful and will save you some gas.

[xbgurlbzzz]

ok here is another dumb questions... Do the manuals have this button because I looked on my dash and could not find it? Maybe I am just misunderstanding that it is only for automatics... can someone clear this up for me please!!

[PCH]

Automatics only.

[Calesta]

Originally Posted by PCH

That's a pretty good explanation but let me add something from my personal experience.
--snip--
I usually leave the button alone, but when i want to have a little more fun driving, i hit it, especially since i wired it to my steering wheel and it's right on my fingertips

Thanks! And I used to play with the button all the time in my dad's Camry too. Just something else to fiddle with while reducing transmission life.

Originally Posted by gravebox

if you want more speed, simply put more throttle down and the ECU will automatically down shift to the necessary gear to accelerate and once at that speed and you start keeping it continuous then it will automatically up shift to a lower gear to consume less fuel.

Originally Posted by xbgurlbzzz

ok here is another dumb questions... Do the manuals have this button because I looked on my dash and could not find it? Maybe I am just misunderstanding that it is only for automatics... can someone clear this up for me please!!

That's why automatics are called automatics... a manual transmission can't automatically shift into a taller gear for you. If you want overdrive, just shove it into 5th. That's your overdrive gear. FYI- on a lot of 6 speed transmissions, both the 5th and 6th gears are overdrive.

Originally Posted by PCH

Automatics only.

Hence the name.