AirForce2004

Hi Im brand spankin' new to this forum. I bought a 2004 mustang GT last month and spoke to a couple people about upgrading. Im going to follow somebodies advice and upgrade my gears first. I want to put in a 4.10 but will this throw my speedo off? If so how do I fix that? Im buying a new set of gears for 160-170 and the instal is around $150, are there going to be any hidden costs? Thanks for any help
BTW its manual
Also. this forum seems to hate 4.10 gears. Should I go with something else?

bull8t

Hmmm, Ive never heard anyone talk bad about 4.10's. Im looking to get a set in the future. Sounds like you got a pretty sweet deal on them. I think you'll need a speedcal to set your speedo right....not sure though, maybe some guys whose done the swap can help you out better.

chriscindy6369

Depending on where you plan on driving the car, with a 5 speed tranny i'd personaly go with 3.73's and 4.10's if you had an auto., But either way it's up to you. Good luck with the car.

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Dan04COBRA

I find the best prices for 4.10 gears or 3.73's here:

http://www.mustangtuning.com/rearend.html

Also, don't get caught up in the 3.73/4.10 gear debate. For WHATEVER reason, some people here with 94+ GT's do not and will not ever understand that their 5 speed transmissions are geared HIGH for GAS MILEAGE (Ford exhausted every effort possible to save gas), 3.73's in a 94+ GT are like 3.55's in a Fox Body, WORTHLESS!!!!!!!!!!!!! Go with 4.10's or NOTHING at all!!!

mdvaldosta

4.10's sound like alot on a 4.6 because alot of people are still stuck in the 5.0 days. The 4.6's have larger tire sizes and different transmission gear ratios. Ford kept the same rearend - so the rear gears had to be different to compensate for these changes in order to get similar driveability. For example, lets compare gear swaps in a 5.0 vs a 4.6:

most stock 5.0 = 2.73, changing to a 3.73 = a 27% increase in engine RPM's / going to 3.55's = a 23% increase
stock 4.6's are 3.27's, changing to a 4.10 = a 20% increase in engine RPM.

Thats why so many people get pissed when the put 3.73's in thier 4.6, its hardly any difference at all. 4.10's on a 4.6 actually make less of a difference then going to 3.55's on a 5.0. Alot of 4.6'ers (especially the 4v) are running 4.30's.

Don't fear the gear my friend, or you will be disappointed.

Dan04COBRA

I don't see why the 3.73 boys fail to believe it! We've had how many members switch from 3.73's to 4.10's?

mdvaldosta

Their still stuck in 1992?

04mustang

hey dont the 4Vs start with 3:55. i got a spec sheet here and it says mach1s have 3:55.
so is that why they go to 4:30s? how do u think the 2V would handle 4:30. im thinking gears a lil down the road and i have my eyes on 4:10s but considering 4:30s. are 4:30s maybe going a lil to far for a 2v. let me know what u think.

Razor19

How badly does 4.10's affect your gas mileage. I've heard some people say you will only see the difference if you are making a long trip that is all freeway, and I've heard some people say you will see a big difference no matter what kind of driving you are doing?

mdvaldosta

Higher gears are more because they rev higher - Ford may have put in a higher rear gear in those cars because they were geared more towards the performance oriented crowd, just speculation. The reason I wouldn't do 4.30's in a 2v is because your gonna be right at redline when cross the traps at the track in 4th gear, so any kind of power increase is gonna have you either letting off the gas (bad) or shifting into 5th at the track (bad). As my power increases (and it will) and I start getting deep into the 12's (I will) then Im gonna have to probably drop my 4.10's for 3.90's or get my redline raised to 6500+, which I really prefer not to do but I won't decide till I get there.