4ZZS

I see lots of comments that people should get different gears as part of their modifications.
I don't understand what the different gear numbers mean and how much improvement they would make in acceleration or other driving.
I have a 2002 GT Convertible (4.6L, automatic). My first and only modification has been an SLP LMII catback exhaust, which added some acceleration and lovely sound. I'm looking for my next mod.
Can someone explain the gears that I have and what performance improvements I would have with different gears (3.90, 4.10, etc.)? Do they effect just the low end or do they also effect highway driving?
What type of a shop do you need to go to for having different gears installed? What kind of costs would I be looking at for the gears and installation?
I hope someone will spend a little time at the keyboard edumacating me, so I can consider whether to pursue this.
Thanks.
Ken

Supercharged98GT

Gears are one cheap way to help improve your acceleration in any car applicable. Think of it as this, in the 1/4 mile you have one really long gear throughout the entire race, or you have 3 or even 4. You are shifting quicker with lower gear ratio's(ex - 4.10's), which means you are in your peak power and tourque rpm's more, than higher gear ratio's. If you do alot of highway driving and want somewhat good mileage than put in 3.73's, if you don't care as much about mileage and want more performance than put in 4.10's or higher yet. Personally thats what I have is 4.10's and would recammend, but it is up entirely to the person. You are looking anywheres to 200 to 300 for install and you can pretty much get them installed at any Service Garage but I would get them installed at a decently known shop if I were you. It is usually worth spending a lil more and getting the right service. Put some gears in, for the cost it is one of the best mods you can do. You will be happy with either gear upgrade you choose.

4ZZS

To Supercharged98GT.
Thank you for the information.
So, the higher the number (4.10 vs. 3.73) means faster acceleration, right?
Does this mean that the car will shift from 1st to 2nd at a lower speedo reading? The same from 2nd to 3rd, etc?
Do you know what gear ratio is in the OEM package that I have right now?
How many different ratios (4.10, 3.73, others?) are there for my car and would I buy them "somewhere" and take them to a Service Garage, or have them get them?
Thanks for the help.
Ken

Supercharged98GT

Yes, the higher the number, the faster the acceleration, but it is actually a lower gear. It is more challenging to get better traction with lower gears too keep in mind, but stock you will be o.k. Once you get more horsepower, just get bigger and better tires and you'll be fine.
The lower the speed you will go from gear to gear with lower gears, but you will also get there faster though.
There is many different gear ratios for you car, look into it a little more and decide what it is you actually want.
Alot of performance stores carry gears, as well as ford, and they will install them for you too.

Dave2000GT

Stock gears are 3.27 for 99-'04 GT's

Commonly available gears are 3.73, 3.90, 4.10, 4.30

To figure out your RPM at a speed, take your present RPM (with stock 3.27's) and multiply for example for 4.10's: RPM * 4.10/3.27 will give you your RPM with the 4.10 gears.

You just get added acceleration through mechanical advantage of lower gear ratio.

justingt

Currently you are running 3.27 gears in your car. Now the previous posts are correct about there being many gears for mustangs. Personally I would go with 3.73. Unless you're planning on competitions at the strip you're not gonna need 4.10 IMO. Now just to let you know before hand the choice of gears is a hotly debated topic you're gonna get yells for 4.10 and yells for 3.73 mostly either way you'll be satisfied. Now personally I'd go with ford racing gears, but that's just me.

4ZZS

Is a Ford dealersip a reasonable place to get the Gear job done?
What is an estimated loss in MPG when going from the 3.27 to the 3.73 gears? My current MPG is 21-22.

Dave2000GT

You should lose 1-2 mpg highway, but theoretically stand to gain some city mileage, but because of the fun factor of gears youll be more tempted to step on it, so that might not happen.

Dave2000GT

I wouldn't get them done a the Ford dealership becauase they are always a ripoff (dealership service rates). The place place to get them is a performance shop that specializes in aftermarket stuff, or else a transmission/rear-end shop.

Also, nobody mentioned it yet but you'll need to get a tuner (Diablosport or X-calibrator etc..) to calibrate your speedometer with the new gears and also help the transmission adjust the shift points.

jdaniel

With my 4.10's in my GT I was getting about 300-350 miles to the tank on the highway and maybe 200-250 in the city if I didnt lay into it much.