Red02GT

I've spent 30 minutes searching. No answer.

I just purchased an 03 GT automatic. I'm sure it has gears, not sure if they're 3.73 or 4.10.

At anyrate. I've found out that the speedo gear doesn't work for 99+ and the Speed Cal only works for 5sp vechicles. Sooooo, how do I fix the speedometer and odometer in an 03GT automatic?

MoKo_04GT

all you need is a tuner to fix it. it'll give ya a few extra horses too. go to
www.brenspeed.com
and check out the x=cal tuner!

blowngt2419

yep just buy an sct tuner and you will be good

Red02GT

Ok, for them to send it to me, they need some info, so I've gotta find out exactly what's on the car before getting this right? Otherwise the tune will not be effective. I've seen tuners that are asking for things like injector size. Is this common? I didn't anticipate another $400 on the car right away, but I guess I better hurry and get it done.

Obsequious1

Jack your rear up ( both tires if you have posi ) and mark your drive shaft. Spin your tire1 complete revolution and have someone count how many times the drive shaft spins. If your drive shaft makes like 3 3/4 revolutions then your car probably has 3.73. A little over 4 and you probably have 4.10 ........and so on....

MoKo_04GT

there is a gear calculator around here somewhere, where you can type in what rpms you are at while going "x" amount of mph = "y gears" which would be easier. not sure where it is tho.also they will ask for your computer code, which you can find on a sticker on the outisde of your card computer. which is located under the passanger side kick panel. if all everything else is stock, like injectors and sutch, then just tell them injectors are stock.

MoKo_04GT

actually now that i think about it....i dont think they are going to be asking you what gears you have because you make those changes yourself using the tuner. iand im pretty sure they didnt ask me about my gear ratios when i ordered mine (although they did ask what all mods i have done)the reason they ask about certain mods tho, is so they can adjust the tune for your car accordingly. you may want to order over the phone (like i did) incase you come up with any other questions, you can ask them. they are very helpful/nice.

98MustangGT46

Just read your post thoroughly. The info i entered you had already tried. Good luck.