[1REASUN]

I have a 1999 Automatic v6 3.8L stang. I have decided that I am FOR SURE getting the SCT SF3 tuner from AmericanMuscle.com

but I have seen that I can get a package deal thing which includes my choice of 3.73 gears or 4.10 gears.



Now time for the questions....


1.a) is it true that stock our gears are 3.55 or 3.27?
.b) if so, would 3.73 really make all that difference?

2) I also don't know which gears I should get, either the 3.73 or 4.10? Could you make suggestions and why?

I also noticed the in the AM package deal there is an option to

Add 8.8in Traction-LOK Rebuild Kit w/ Carbon Discs. What does that do?
and

Add 8.8in Bearing kit 21201 at $75
OR
Add 8.8in Installation kit 21203 at $36? and what is the difference between those last two as well?

*i drive a lot on the highway too*



Thanks much
*maybe i should split this into different threads?

[mooses]

Stock gears are 3.27. Usually it's suggested to do: auto - 4.10s, manual - 3.73s. Did you swap a GT rear already? If not, you have a 7.5 rear, not 8.8.

[orson250]

i have read that 4.10's don't develop a significant drop in highway gas mileage if that helps and that's what i'm getting for my auto.

[stangcharger]

if you can go through the traps in 4th gear with 4.10's then get 4.10's. if you will have to shift into fifth gear like i would then go to 3.73's.

the lose in highway mielage isnt anything. it is mainly people pushing the gas harder to feel the added boost.

[1REASUN]

Originally Posted by stangcharger if you can go through the traps in 4th gear with 4.10's then get 4.10's. if you will have to shift into fifth gear like i would then go to 3.73's.

What do you mean by traps?


and if i get gears, that means i absolutely HAVE TO get 8.8 rear end?

[N29468]

Trap speeds is a track term (13.5 at 100 mph etc.) and no you dont need 8.8 rear end with gears. You only need to think about it if your planning on making alot of power

[1REASUN]

idk by what terms you mean by adding a lot of power? my current mods include: CAI and divorced true dual exhaust. i do about 1-3 mods a year:cosmetics or performance: (i live in MN, so i don't drive when there's snow out)...

NEAR future mods include: SCT SF3 tuner

possibly the gears in which we're talking about...


Future mods: Under Drive Pulleys, LT headers, and other bolt ons + cosmetics

Probably Never mods: forced induction: turbo, supercharge, nitrous




so i do NOT have to get any of the 8.8 items included in the package?

Add 8.8in Traction-LOK Rebuild Kit w/ Carbon Discs. What does that do?
and

Add 8.8in Bearing kit 21201 at $75
OR
Add 8.8in Installation kit 21203 at $36? and what is the difference between those last two as well?


would it be better performance/acceleration if i do?

[mooses]

Originally Posted by 1REASUN What do you mean by traps? and if i get gears, that means i absolutely HAVE TO get 8.8 rear end?

You don't need an 8.8 rear... just make sure you buy gears for a 7.5, and not the 8.8. Are you going to get a new differential too? Usually it's suggested to swap out your open differential, otherwise you'll be doing a 1 wheel peel if you lose traction.

Traps are just a term for the speed you hit at the end of a track run. 99% of us will never have the power to redline 4th before the end of the quarter mile even with 4.10s, so it's almost pointless to even mention trap speed affecting your gear choice.

[mooses]

Originally Posted by 1REASUN idk by what terms you mean by adding a lot of power? my current mods include: CAI and divorced true dual exhaust. i do about 1-3 mods a year:cosmetics or performance: (i live in MN, so i don't drive when there's snow out)... NEAR future mods include: SCT SF3 tuner possibly the gears in which we're talking about... Future mods: Under Drive Pulleys, LT headers, and other bolt ons + cosmetics Probably Never mods: forced induction: turbo, supercharge, nitrous so i do NOT have to get any of the 8.8 items included in the package? Add 8.8in Traction-LOK Rebuild Kit w/ Carbon Discs. What does that do? and Add 8.8in Bearing kit 21201 at $75 OR Add 8.8in Installation kit 21203 at $36? and what is the difference between those last two as well? would it be better performance/acceleration if i do?

People swap 8.8 rears because they won't break as easily as our 7.5 rears. If you are right about your 'probably never' mods, then you do not need to get an 8.8. You don't need any of those parts you listed. Are you SURE you are buying 7.5 gears? If you buy 8.8 gears accidently, they will not fit your car.

[1REASUN]

Originally Posted by mooses People swap 8.8 rears because they won't break as easily as our 7.5 rears. If you are right about your 'probably never' mods, then you do not need to get an 8.8. You don't need any of those parts you listed. Are you SURE you are buying 7.5 gears? If you buy 8.8 gears accidently, they will not fit your car.

When/If I buy them, I'll make sure of it, thanks very much. I'm not sure if AM has 7.5 gears of 4.10, i'll try to figure that out.



and by "break"....that sounds kind of scarry? anyone hear of this happening? or what is the likely hood? ....of course i like to "get on'er" but i really dont want a loitering ticket, have to call tripleA and get my car, and worry about breaking my gears

[yellowstang6r]

Originally Posted by 1REASUN When/If I buy them, I'll make sure of it, thanks very much. I'm not sure if AM has 7.5 gears of 4.10, i'll try to figure that out. and by "break"....that sounds kind of scarry? anyone hear of this happening? or what is the likely hood? ....of course i like to "get on'er" but i really dont want a loitering ticket, have to call tripleA and get my car, and worry about breaking my gears

Yes they have 4.10s and 3.73s for our V6's. I will try to find that link for you. A recommendation tho, get a T-Lok too, it will make both of your rear wheels spin (helps w/ traction, especially in the snow/wet)

Breaking the rear end, yes a big problem. Dont worry about it, with the mods you are looking at. It would only be a concern when you would approach 300+hp which (no offense but) I dont see that ever happening in your car w/o a Turbo or SC.

[yellowstang6r]

Gears 4.10 Gears for 7.5 Rear end at AmericanMuscle.com - Free Shipping!

Bearing kit Rear End Installation Kit at AmericanMuscle.com - Free Shipping!

T-lok Ford Racing 7.5" 28 Spline Traction - LOK Limited Slip Differential at AmericanMuscle.com - Free Shipping!

Gear Oil (need 3 quarts) Royal Purple Max Gear 75w90 Gear Oil at AmericanMuscle.com - Free Shipping!

Some say you will need friction modifier, others will disagree but here is a link for that M-19546-A1 Ford Racing Friction Modifier


Thats everything that you'll need other than the tuner and someone to install them...I think that def deserves some major reps

[ByPopularDemand]

Originally Posted by orson250 i have read that 4.10's don't develop a significant drop in highway gas mileage if that helps and that's what i'm getting for my auto.

4.10's...my stang with em still cruises at a lower rpm than my n/a eclipse in the freeway

[mooses]

Originally Posted by 1REASUN When/If I buy them, I'll make sure of it, thanks very much. I'm not sure if AM has 7.5 gears of 4.10, i'll try to figure that out. and by "break"....that sounds kind of scarry? anyone hear of this happening? or what is the likely hood? ....of course i like to "get on'er" but i really dont want a loitering ticket, have to call tripleA and get my car, and worry about breaking my gears

Make sure you go here Coupon Code to get the discount code, it should save you quite a few bucks.

Just FYI: It's not the gears that break, it's the differential. The 7.5 tlok is the weak link in our rears (if you get it installed, of course - it's not stock on our cars). Most people go with a tlok because normally they don't have the power to break them. Unfortunately, they can even break with only a few mods. A hard launch will shatter the spider gears even if you don't have a bunch of power. With an auto, though, most likely the only way you'll break it is if you get a higher stall and some slicks. You'll be fine.

[1REASUN]

Originally Posted by yellowstang6r Gears 4.10 Gears for 7.5 Rear end at AmericanMuscle.com - Free Shipping! Bearing kit Rear End Installation Kit at AmericanMuscle.com - Free Shipping! T-lok Ford Racing 7.5" 28 Spline Traction - LOK Limited Slip Differential at AmericanMuscle.com - Free Shipping! Gear Oil (need 3 quarts) Royal Purple Max Gear 75w90 Gear Oil at AmericanMuscle.com - Free Shipping! Some say you will need friction modifier, others will disagree but here is a link for that M-19546-A1 Ford Racing Friction Modifier

+1


anyone have an estimate cost to have this install done? and would i necessarily want all these?


(scarred the tlok breaks)

[mooses]

Originally Posted by 1REASUN +1 anyone have an estimate cost to have this install done? and would i necessarily want all these? (scarred the tlok breaks)

Yeah you'll want each thing that he listed. You'll have to go around to shops to get quotes. I'd say a good installation price is around $300-400, but you'll find lots of shops that'll quote you more. You might get lucky and get even lower than $300 though.

edit: and the tlok will be fine, don't worry about it.

edit2: and make sure you get that coupon code from my last post, it'll save you 6% or something like that

[1REASUN]

Originally Posted by mooses Yeah you'll want each thing that he listed. You'll have to go around to shops to get quotes. I'd say a good installation price is around $300-400, but you'll find lots of shops that'll quote you more. You might get lucky and get even lower than $300 though. edit: and the tlok will be fine, don't worry about it. edit2: and make sure you get that coupon code from my last post, it'll save you 6% or something like that

yup, already know about the code, thanks tho



someone posted earlier about that i only needed the gears and nothing else. is that incorrect?

[ewells2420]

I dont know where some of you are getting your information, but as having 4.10 gears in an auto stang I can tell you there is a BIG DROP of MPG on the highway over 50mph.

At about 55-65mph im going about 2.5k RPM which is going to burn A LOT more fuel that before cruising about 1.5k-2k with 3.27 gears (stock).

I mean its not HUGE, but its big enough to almost regret getting 4.10s once I have to do highway driving. If you dont, then by all means gets 4.10s.

But If I were you, get 3.73s. Its still a really good gain and sensible.

[1REASUN]

Originally Posted by 1REASUN someone posted earlier about that i only needed the gears and nothing else. is that incorrect?

?

[mooses]

Originally Posted by 1REASUN yup, already know about the code, thanks tho someone posted earlier about that i only needed the gears and nothing else. is that incorrect?

I just read through every post in this thread and no one mentioned that you only need gears and nothing else.