Overdrive button in automatics

Mink

I drive a 1.8 automatic Toyota Carina.

On the automatic gear shift there is a little button. When you press it in an indicator light comes on on the dash saying "O/D Off" in bright orange. When the button is not pressed, no indicator lights come on.

What is the purpose of the Overdrive? Are you supposed to have it set to "O/D Off" all the time & then have it on when you're going 80km ph+

I would have thought that the warning indicator light comes on because you're not supposed to have it off. I'm really confused

robtri

wiki says it all

Overdrive can refer to two different things. An overdrive is a device which was commonly used in automobiles to allow the choice of an extra-high overall gear ratio for high speed cruising, thus saving fuel, at the cost of less torque. Usually the final or top gear is called overdrive. Non direct drive gears increase torque multiplication at the expense of higher engine rpm and thus, decreased fuel economy.
It also refers to a combination of gearing inside a transmission or transaxle which results in the output speed being greater than the input speed. In the latter case, "overdrive" does not refer to a physically separate identifiable part/assembly.

rocky

I think when you have it "on" there's an extra gear, when it's off you have one less gear so the car feels more responsive in town.

You can leave it on, unless you're towing something (and need a bit of extra torque)

Edit: yeah ^^

2 Espressi

Edit: What they said^^^^, I 'm waay too slow!

Mycroft H

Mink wrote: »

I drive a 1.8 automatic Toyota Carina.

On the automatic gear shift there is a little button. When you press it in an indicator light comes on on the dash saying "O/D Off" in bright orange. When the button is not pressed, no indicator lights come on.

What is the purpose of the Overdrive? Are you supposed to have it set to "O/D Off" all the time & then have it on when you're going 80km ph+

I would have thought that the warning indicator light comes on because you're not supposed to have it off. I'm really confused

I'm gonna guess that the carina is a 4 speed auto.

Overdrive is basically where where the engine uses the 4th gear for cruising. When disengaged, the engine will only use the 3 foward gears

Or it can be a seperate part on some older classic cars where the ''Overdrive'' was a seperate part to the gearbox. This device basically lowered the overall ratios of all the gears which was ideal for cruising

EDIT: way waaay too slow

Volvoboy

OP i have a 1.6 Carina auto, i always have the O/D on, makes no diffrence only thing it does it knock it from a 3 speed to a 4 speed auto.

Mink

Volvoboy wrote: »

OP i have a 1.6 Carina auto, i always have the O/D on, makes no diffrence only thing it does it knock it from a 3 speed to a 4 speed auto.

Ok so you wouldn't have the indicator light on saying "O/D Off" then?

I saw the bit from Wikipedia above but it's not quite sinking in

metzengerstein

when i press my sports button/overdrive button,its like the suspension changes it feels more gripy and strudy but also the petrol needle goes down at a rapid rate so not very fuel efficient can feel a lil bit more power but not alot

Esel

betafrog wrote: »

Shamelessly ripped from wikipedia: ...

Edit: Crap Robtri beat me to it :-(

At least you had the decency to cite Wikipedia, whereas Robtri just came across as a wannabee motor engineer. :pac: