When do I use the overdrive system in my car? Some one said I should put my car in overdrive when I reach a speed of 55mph. Is that true. Or should my overdrive be on all the time? Please help me with this matter.

If it is an automatic, leave it in overdrive at all times. If it is a manual, shift normally up through the gears, if top gear works for the conditions, then use it. What kind of transmission do you have? What does your owner’s manual say?

I have a automatic Kia Rio. The manual doesn’t say much. It says the transaxle will not shift to 4th gear until the O/D system button is pressed. It sounds like the O/D is always on. Should it be off while I am driving at lower speeds to increase my gas milage? and turned on when traveling at higher speeds? My car doesn’t go into 4th gear unless the o/D is on.

Leave it on at all times, the transmission will shift properly for itself. Using O/D will improve your mpgs. The only exceptions are when towing, or when going down a long down hill where you want to use the engine to help control your speed.

If you have an automatic transmission and a light comes on when you press the OD button that reads “overdrive off,” you should leave it on. The only reason most people disengage the overdrive is for towing or hauling heavy loads.

If you feel the transmission “hunting” (changing gears frequently) while traveling in the 40-50mph speed range, you can eliminate this useless shifting by locking out the overdrive until your speed is above 50 and you are out of urban traffic.

Frequent and unnecessary shifting can cause premature transmission wear and eventual failure. It will fail soon enough as it is, why hurry the process along? When driving in city traffic, I lock the overdrive out…

Normally you should leave it on, but there are some cases when you might want to turn it off. The first (and most common) case is when you’re going down a long hill and you want to drop one gear so that you don’t need to use your brakes as much. The second case is when you’re going up a long hill and the transmission keeps shifting between overdrive and the next gear frequently, which can be annoying. The third case is when you’re towing, if that’s what the owner’s manual says to do.

I agree with all the above.

In the good old days (the 1960’s and earlier), Borg Warner made an overdrive unit that was a small transmission behind the regular manual transmission. When the overdrive was used, after the car was going faster than 28 mph or so, one would let up on the accelerator and a higher gear would engage. I used to wonder why the cars were equipped with this overdrive unit instead of adding an overdrive gear to the manual transmission. I finally guessed that too many motorists would shift into the top gear too soon and lug the engine.

With today’s automatic transmissions, the shift to overdrive is done automatically and at a speed where the engine won’t lug. You should be fine always leaving the overdrive engaged.

I can attest to that being a fine thing to do. I don’t have a way to turn it off - but there are times that I want to be able to - exactly the instances that Caddyman mentions.

Or you can also just leave it alone.

On all the time except to enhance engine braking, towing and driving at sustained low speeds as many manuals suggest. I don’t use OD in hilly areas where speed limits of 45 or less are easily exceeded while coasting and the engine braking gives you a little extra time to monitor any increase. Helps save on brakes and speeding tickets. Otherwise, they are called automatics for a reason.

Thank you everyone for your answers.My car manual didn’t say much on the subject. I tried calling a few people and they wanted me to bring it in.(I’m single,not stupid)I was happy when I ran into this site. Thanks to everyone!!

These optional overdrives ONLY engaged when the DRIVER pulled out the overdrive handle and the cable control engaged the overdrive unit…

The only time I don’t use overdrive is at low speeds with ups and downs in town where the car shifts up and down and makes it difficult to maintain a steady speed or when climbing hills and the transmission keeps shifting between overdrive and out of overdrive. That’s it, only when it bothers me.

Yes, the overdrive handle had to be pulled out to engage the overdrive unit. However, the overdrive wouldn’t kick in until tha accelerator was released. With the overdrive engaged, the car free wheeled until the accelerator released and the overdrive gear engaged. There were actually five forward speeds: first, second, overdrive second, high and overdrive high.

cigroller, I’d bet you DO have a way to turn it off. You either have a button or you have the option on the gear selector. If you have P N O D 2 1 in D you won’t be using overdrive.

It’s a good question, you do well to ask.

Your overdrive ain’t gonna come on anyway 'till you reach a cruising speed.