question for car savvy people

Generally speaking, overdrive (O/D) is the highest gear in the transmission. On most automatic cars have 3 speeds and Overdrive (forth speed). Overdrive allows the engine to have a less rpm when at a higher speed in order to have better fuel efficiency. When you switch it on, you allow the transmission to shift into overdrive mode after the certain speed is reached (usually 30 - 40 mph depending on the load). When it's off, you limit transmission shifting by third speed. In normal driving condition the overdrive should be always on. You may need to switch it off if you drive in mountains area. The automatic transmission automatically shifts from OD to the 3rd gear when it feels more load. When it feels less load it shifts back to the O/D, but under certain conditions, e.g: driving uphill or towing a trailer, the transmission can not decide to stay in OD or to shift into 3rd gear and it starts to shift back and forth. That's the time you may switch it off and help the transmission to decide. You also may need to switch it off when you want to slowdown using the engine braking, for example, driving downhill. check your owner's manual that should be able to help you

only when towing or climbing long grades and 4 wheeling turn it off as this is a small step for saving fuel on open flat highway other than that dont mess with it also your owners manuel should tell you this

Okay, my husband says us never us overdrive when pulling stuff like a camper or trailer or boat. That's about all I know about it.

When you use the overdrive your car's engine speed goes down. This will save gas and wear and tear on the engine. Should use it most of the time and especially on highway. Hope this helps. Did you read your book with the vehicle, they usually give you pretty good information!

Overdrive you would use on the highway and so on. Pretty much if your constant speed is 60 mph and up use over drive. But I keep my over drive on all the time.. It doesn't really matter. It just gives your car a faster pick up when you hit the gas petal.

For normal day to day driving you should leave your transmission with the overdrive on. The Transmission controller (tranny computer) will determine if your Jeep should shift into overdrive or not. If you have it in the off position, it will override the computer not allowing your transmission to go into overdrive. If you are doing any heavy hauling, mountain climbing or off roading in your Jeep, then you would want to turn your overdrive to the off position.

The purpose of the overdrive button is to increase the life of the transmission. The overdrive is the weakest part of an automatic transmission. When in an area where your speed is going to vary from fast to slow quite a bit, you do not want the overdrive functioning. If the overdrive is on when speed is varying much, the overdrive will constantly be kicking in and out. This will cause early failure of the automatic transmission. I once was a rural mail carrier and knowing the purpose of this button saved me a lot of money.

When I bought my Xterra a few years ago I had the same problem. I accidentally hit the button once and didn't know it for a few days. Everyone has told me to leave it the way it is automatically and only change it if I am hauling things or on steep hills.

Overdrive (off) would be for in town stop and go driving. Overdrive (on )would be for interstate and highway driving.