# what is overdrive



## thepit56 (May 26, 2006)

I am new to driving automatics and my stang has overdrive, what does it do and when should I use it.


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## BUDFAN8 (Apr 11, 2007)

most modern vehicles can be place in overdrive all the time. overdrive is a higher rated gear much like the highest gear to a manual transmission. 

the only times i dont use overdrive in my truck are when im driveing slow on backroads and feel the transmission shifting up and down alot or when pulling a load those times i just use drive.


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## Raylo (Feb 12, 2006)

In modern cars overdrive is simply any gear ratio which is numerically lower than 1:1. In other words, the output shaft of the tranny will be turning faster than the engine crank shaft. So instead of being multiplied, transmitted torque is actually reduced. But so is engine RPM which saves gas at highway speeds due to less cumulative friction and pumping losses. The same used to occassionaly be accomplished with 2-speed differentials in the old days.


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## mack1 (Nov 27, 2007)

Hi thepit56 and welcome to TSF

Overdrive is one of the best features they put on cars. I don't know when they started including them on cars, but I had a 50 model Ford that had it. So, not a new idea.
It works just like budfan8 and Raylo said, a gear above the high gear in the car. Leave it in. It works automaticly with your footfeed. It only switches in after you get up to a minimum speed (around 45mph I think) and you let up a little on the accelerator. From there on up, it will work. When you reach crusing speed, and back off on the foot paddle, it will switch in. When it feels a load (pushing down on the accelerator or going up a hill) it will down shift to normal high gear. It is all automatic(even on standard shift cars) and you don't have to do a thing.

Have fun with your stang.
Mack1


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