A few weeks ago I bought an 01 GT and on my way home I noticed that it had gears but I am not sure what is in there. My speedometer is off a good amount does anyone no if I can correct the speedometer with a factory FORD scan tool. I have an NGS scanner but can't figure out how to do it. In my 01 Explorer I can correct it through the GEM module but on my Mustang I can't.

 

This will fix your speedometer

http://www.americanmuscle.com/ford-s...tool-9410.html

Jack up the rear end of your car so both wheels are off the ground, put a mark on the drive shaft, put the car in neutral and rotate one of the wheels all the way around. How many times your drive shaft rotates during the wheel rotation tells you what gears you have in your rear end. If it rotates 3 1/4 times, your have 3.23's. If it rotates 3 3/4 times, you have 3.73's. And if it rotates just over 4 times, you have 4.10's. Hope this helps.

 

That thing has nothing but bad reviews, there has to be another way,

 

A SCT tuner will help correct speedo plus you can load custom tunes. Bonus

 

Are you talking about the handheld tuners?

 

Yes

 

I installed one in my car after I bought my 4.10 gears and it works perfectly fine.

 

I used this

http://www.streetbeatcustoms.com/AM-...-50045/642935/

same thing basically, it worked perfectly on my 97 mustang but I would go with the handheld tuner if you can afford it.

 

Agreed Tuner

I wonder if you can just replace a gear ratio on the speed cable? or is it all digital now?

 

Handheld is the easiest way to adjust it