What is overdrive? I've done some searching, but haven't gotten a really good answer. When should I drive with overdrive engaged? I have a V6 auto, if that makes any difference.

 

Overdrive is the 4th gear on most auto trannys. Some 5 speed auto tranny that is 5th gear.

I could get real technical but basically overdrive is the last gear (yes there are trannys with 2 overdrive gears) and it spins faster then the engine due to gearing.

You want to use Overdrive virtuall all the time except when you are first starting out on a real cold day or if you are towing/overloaded. Under towing conditions the using overdrive creates a lot of extra strain on the tranny and causes to to get haooter. Heat + Auto tranny = $$$$

Basically, it allows you to get better MPG and drive at highway speeds with low RPM's.

 

Gearing that allows the output shaft RPM to exceed the input RPM on a transmission. Ratio of drive in a gear box is 1 to 1. Over drive is 1 to < 1.1.
The point is lower engine (imput) RPM at higher (output) speeds....mostly for fuel econmy.

 

Usually overdrive is automatically disabled by the ECU until everything's warm. Most just leave it on and ignore it. turn it off if you are towing or running up a long hill (to prevent gear "hunting"). you can also turn it off on long downhills to provide a little bit of engine braking and prevent overheating the brakes

 

Thanks for all the answers.

This is just what I was looking for. I use it virtually all the time so I was doing what I should have been.

Thanks again for the replys.

 

when driving in the mtns of NC, Va and Tn, i always keep the OD off. it drives me nuts when the tranny is constantly shifting up and down..

 

That's probably the most annoying thing about my 4runner. I'll be going up not even a semi-steep hill and it will jump about 500-100 rpm.

 

yep everytime i go up a steep hill on the highway it sounds like my 4runner constipated and having trouble going to the bathroom.

 

LOL, that is great! If i had any more room in my sig it would go in there.