Ok I have a automatic car with overdrive on my shift knob. I never use it and I was wondering if I could buy a new automatic shift knob and it would fit even with the overdrive. Now I know there wouldn't be a button for the overdrive, but it doesnt matter cause I dont use it. Would the new shift knob fit? or would the overdrive get in the way?

BTW, what exactly is overdrive for anyway? I just leave mine on, but my car also has a button to turn it off on the shift knob

I think overdrive just keeps the car in higher gear to improve fuel economy.....not exactly sure though

yes, over drive does up the gear ratio.
It should be turned off for low speed and performance driving to extend the life of your transmission and also to help with acceleration (when needed). It should also be turned off when going up steep hills.
the aftermarket whifter will work fine, and contact the company to see if they make a model with an overdrive button.

O/D is 4th gear on most auto trannies. try driving along at 50mph, then hit the O/D button to turn off O/D and you'll hear the car shift into 3rd gear. in most situations theres no need to turn off O/D, only if going down a mountain and you want to keep yourr car in a lower gear so you dont have to ride the brakes

O/D is 4th gear on most auto trannies. try driving along at 50mph, then hit the O/D button to turn off O/D and you'll hear the car shift into 3rd gear. in most situations theres no need to turn off O/D, only if going down a mountain and you want to keep yourr car in a lower gear so you dont have to ride the brakes


This is the "old-style" of O/D.

The true O/D function of an automatic changes the final drive gear on the output shaft on the transmission. So basically if you have a 4 speed auto, it's still a 4 speed with the O/D on or off. The difference is about 5-10% taller gears (all of them) with O/D on for increased fuel economy.

In the situation you described above, it's not shifting into 3rd per se, it's hitting a lower geared 4th.

This should get everything cleared up.I finally got it.

http://auto.howstuffworks.com/automatic-transmission8.htm