'05 Differential

[2005GT]

Just got my 2005 Silver GT Coupe. It has the automatic so the differential is 3.31
I'm looking for some advice re changing to a 3.73
I'm retired and this won't be my primary driver so, for example, the impact on mileage is no problem. Right now, changing the rear end is the only mechanical mod I've planned (but by next spring I expect to have either a Kenne Bell or a Saleen supercharger on the car.
Meantime, apprec input re this first change, especially from those of you who have the knowledge/experience with this....
Thanks, Jim (2005GT)
"2005 Mustang - dolce stil nuovo

[squeeeg]

I am assuming the 05's have a computer controlled speedo like the 99-04 so you will need to calibration unit to get your speedo right. I haven't seen them anywhere but i am sure they are out ther. Try Pauls High Performance, If anybody has one it is him.

[SNW BLUE BY YOU]

Squeeg is correct, Paul's High Performance, Steeda, Dallas Mustang, etc. have calibration units, or it can be done with tuning
i.e, Superchips Custom Tuning, which is done through the DLC
connector.
You can check w/ them now, or give it a few weeks.
But I will say the aftermarket came to the table prepared, so most anything you would like is available right now.
Enjoy your ride!

[squeeeg]

Do the 05's still have that 8.8 rear?

[skooter]

Are we talking the rear end gears now? I've always heard to leave that to a professional shop. A lot of things you have to get right or else...

[SNW BLUE BY YOU]

2 answers here, yes the '05 has the same 8.8 rear end. It is for the most part used in all Ford products in different configurations.
It is what is called the corporate rear gear, along with 9.75 & 10.25 in trucks.
Yes if you do not have the proper tools,and experience to swap gears, leave it to the pros. It is never as simple as the rags make it look.
I do 8.8's with my eyes closed, but there is always one that will bust your chahones.

[dusterdogooder]

Y'all were always talking about the rear-end... I don't know what other gears you would be changing. The tranny is easy, just swap out to a different set-up in the tranny. Anyways, I think that the 3.73 gears in the rear would be a good upgrade, but I wouldn't worry about it too much untill you get a few of the other "power" upgrades accomplised. The gears aren't really going to affect anthing until then unless you're just trying to get that out of the way before hand.

[JimG]

I have a question, since the acceleration for the manual and auto are close but the diff ratios are spread like that does that mean the auto has lower gear ratios. I'm trying to make up my mind between ordering auto or manual.

Thanks for any info you can share.

Jim

[SNW BLUE BY YOU]

Jim,
The choice between the stick or slushbox is entirely up to you
One is not technically better than the other
Most people choose the stick in a sporting car for exactly that reason, it's more sporting, the driver is more involved.
Some of the fastest drag cars in the country have autos. You will not however find an auto in an SCCA or NASA racecar
Its simply a matter of preference.
I also have to respectfully disagree w/ dusterdogooder on the gear swap. This should be one of the first things you do.
Although not having the effect of a gear swap in the early days, when a change meant going from a 2.73 to a 3.73 or lower gear
because Ford has seen fit to install 3.27 or 3.55 gears, the effect of torque multiplication can not be denided.
If you go back as far as me, the 10 min. tune up was : a K&N filter a bump in timing, a TPS adjust, and a gear swap. With slicks, a 5speed LX notch would go 12's.
Taking into account the weight of the '05, a 3.90 gear would be the tallest gear I would want.
Remember, the higher the number, the shorter or lower the gear ratio, the lower the number, the taller or higher the ratio.
You can not change the laws of physics!
" Give me a long enough lever, and I can move the world "
I could be wrong, but I dought it.

[skooter]

I get jealous every time you post SNW!!!! With that '03 sonic blue Cobra......drool......

[shibby]

I need to find someone to put my 3:90's in the Cobra. I've had them sitting in my garage for almost a year now.

[fo2sh]

hey JIM:
if i were you i would go with the manual without even thinking, i mean hey its a damn MUSTANG a monster. you will need to be in control of it with the manual stick. just like a rottweiler you have to use a good old steel chain

[mj3039]

the 373 is great but i have heard that it slips a lot in the auto trans. I have read also that it will need quite a bit of tunning to get it right.

Again just what i have been told and have read.

GL

[JimG]

SNW, fo2sh,

Thanks for the replies. I want the manual, just having trouble convincing my wife. She has never shiffted. I'm trying to think of a way to push her to my side. I want yellow she wants red, so maybe I can negotiate. Maybe I can buy 2, 1 auto and 1 manual.
Just kidding!

Jim