does it matter if i turn overdrive on or off in my 2003 v6 mustang. i have 3.73's btw

like whats the difference? is it any faster one way or the other?

 

turning it off locks the car out of overdrive, it does nothing else

 

It's basicalyl just a highway gear to save wear, tear, and gas mileage. Think of it as 4th gear, but a gear that's above a 1:1 ratio. if you shut it off, then you car simply will not shift into "4th" and instead will stay in third gear. Other than that aspect, it has no bearing on your performance or speed in any way, shape, or form.

I shut it off in the city to keep it from shifting in and out of OD doing like 40 MPH on the streets as I stop and go. If you floor it and go WOT, it won't shift into OD anyway.

 

You will accerelate the same with OD on or off until you reach redline in 3rd gear.