So I've heard 4.10's with an automatic, 3.73 with manual but why?

TeddyKGB

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Apr 3, 2007
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So I have been doing a bunch of reading on several boards trying to learn as much as a I can about the different gear options and which one would suit me best.

I have a 02 GT with an automatic transmission and I am looking at either a 3.73 or 4.10 gear. Several different threads have people saying if you have an automatic transmission you should go with 4.10 but my question is why? Is there something inherent about the 4.10’s that work better with automatics?

I am not really looking to ever take it to the track, nor look for Honda’s to beat up at night; I really just want to make my GT a bit more fun to drive by giving it more git’up n go.

I am sure this has been asked before but with so many different threads mentioning the word “3.73” or “4.10” it is hard to find the answer.

Thanks!
 
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I have 3.73's in my auto car. However I did this because I knew I was getting spray. If you are not going to get a power adder of any kind I would go with 4.10's or at the very least 3.90's.

The reason is because it gives you advantage when racing standard cars. Unless you have a tuner its hard to get the most out of the auto.

Also read up on the "jerry mod" for automatics.
 
I've wondered that too. I still say it depends on what types of roads your car will see. If you do any sort of long distance driving and have 4.10's in an Auto I think it'd get very annoying very fast, and you'd run out of gear quickly too. Just from personal experience with my 3.73's I wouldn't change up to 4.10's due to the fact that I drive to the lakes quite often during the summer which includes 40 miles of 70-75MPH interstate driving. 2800-3000RPM (forget the right #, its been awhile since I've done the trek now) is bad enough, I couldn't imagine 3-3200RPMS for that long.
 
I have 3.73's in my auto car. However I did this because I knew I was getting spray. If you are not going to get a power adder of any kind I would go with 4.10's or at the very least 3.90's.

The reason is because it gives you advantage when racing standard cars. Unless you have a tuner its hard to get the most out of the auto.

Also read up on the "jerry mod" for automatics.

Imo 4.10s for even auto cars with nitrous or a centri blower.

I have a t trim on my 01 auto and it makes good power, but is still a slug because of the auto. J mod and trans cooler monday, 4.10s ready to go in when the weather gets better.
 
...70-75MPH interstate driving. 2800-3000RPM (forget the right #, its been awhile since I've done the trek now) is bad enough, I couldn't imagine 3-3200RPMS for that long.

I think 70-75 mph with 4.10 gears is about 2400-2600 rpm. That rpm is not too high IMHO. 5th gear is now usable and enjoyable, instead of a dog. I think I would have been disappointed with 3.73 gears.
 
I think 70-75 mph with 4.10 gears is about 2400-2600 rpm. That rpm is not too high IMHO. 5th gear is now usable and enjoyable, instead of a dog. I think I would have been disappointed with 3.73 gears.

Autos only have 4 gears there bucko :D
If you have a manual 4.10's are a must. Once the roads clear off enough that I can drive the mustang on them again I'll try to note the RPM/Speed.
 
propellorhead - I did search for "final gear ratio" but not sure that I found anything specific as it pertains to advantages to have 4.10s in an automatic. Do you remember what the topic specifically was about.

Based on all the great responses so far it kinda of sounds like it is based on personal preference rather than something mechanical.
 
propellorhead - I did search for "final gear ratio" but not sure that I found anything specific as it pertains to advantages to have 4.10s in an automatic. Do you remember what the topic specifically was about.

Based on all the great responses so far it kinda of sounds like it is based on personal preference rather than something mechanical.

Bingo
 
propellorhead - I did search for "final gear ratio" but not sure that I found anything specific as it pertains to advantages to have 4.10s in an automatic. Do you remember what the topic specifically was about.

Based on all the great responses so far it kinda of sounds like it is based on personal preference rather than something mechanical.
If I remember right, it was something like the auto has a higher final drive so you can afford to go with the lower gears. Did you find what the final drive ratios are for the 5-spd and the auto?
 
I looked all over. Wikipedia had them. <roll eyes>

4r70w (auto)
1st: 2.84 :1
2nd: 1.55 :1
3rd: 1.00 :1
4th: 0.70


TR3650 (5 spd)
1st: 3.380 :1
2nd: 2.000 :1
3rd: 1.320 :1
4th: 1.000 :1
5th: 0.620 :1

Looking at 1st to 3rd, the 5 spd has lower gear ratios compared to the auto. In 1st gear, the 5 spd's driveshaft turn 3.38 times for every 1 turn of the wheel. In the auto, the driveshaft only turns 2.84 times to cover the same distance. This is a contributing factor in the better acceleration of the 5 spd. This also means the auto needs more help to achieve the low gear ratios for the improved acceleration. So it's not just a personal preference. There is a mechanical reason for it.

QED.
 
more than half of the people on this forum will tell you go with 4.10's. 4.10's on a DD makes little sence for a car that wont see the track, if your car isnt modded to hell you'll proly even get tired of 3.73's eventually. It is personal opinion, and on a modded car site you're always going to have the majority of people saying go all out, though is it the best? That's for you to decide.
 
Not being a Mustang "expert", I'd have to limit my comments to a more "general" nature. If the gear ratios posted here are correct, I'd say it shows that the manual trans can handle 4.10's better than the auto.
Personally, I think 3.73 is the "perfect" ratio for "most" N/A street cars. I also think that many people choose shorter gears (higher numerically) because they're a no-brainer, cheap way to enhance the acceleration of your car. That's a shame because it's really a much more involved issue.
 
propeller 0 awesome info!


Thanks for all the great responses, this is exactly what I was looking for.

To be honest I was pretty much leaning towards the 3.73 because it is my daily driver and I wasn't out to really try and go toe to toe with someone in my car. Just wanted to make it a little more fun. I just wanted to make sure that I wasn't going to create another future issue for myself by choosing the 3.73 over the 4.10 other than not getting all the acceleration I could get out of it.

I am a newbie at this and have never driven a mustang with either gear so I was trying to determine not only the different options but why folks would choose one over the other.


Thanks again
 
Not being a Mustang "expert", I'd have to limit my comments to a more "general" nature. If the gear ratios posted here are correct, I'd say it shows that the manual trans can handle 4.10's better than the auto.
Personally, I think 3.73 is the "perfect" ratio for "most" N/A street cars. I also think that many people choose shorter gears (higher numerically) because they're a no-brainer, cheap way to enhance the acceleration of your car. That's a shame because it's really a much more involved issue.
How so? If you put 4.10s on an auto, 1st gear would end up with a 3.56 gear ratio. That's only a small advantage over the 5 spd's stock 1st gear of 3.38.
 
propeller 0 awesome info!


Thanks for all the great responses, this is exactly what I was looking for.

To be honest I was pretty much leaning towards the 3.73 because it is my daily driver and I wasn't out to really try and go toe to toe with someone in my car. Just wanted to make it a little more fun. I just wanted to make sure that I wasn't going to create another future issue for myself by choosing the 3.73 over the 4.10 other than not getting all the acceleration I could get out of it.

I am a newbie at this and have never driven a mustang with either gear so I was trying to determine not only the different options but why folks would choose one over the other.


Thanks again
I was afraid 3.73s would be a half-ass mod and something I would regret. I'm glad I went with 4.10s and I have no regrets. It's not all about racing either. It also enhances city driving. 4.10s made the car feel like a 1000 lbs lighter. There's less strain on the motor and drivetrain because gearing multiplies the torque. The car doesn't have to work as hard. Throttle response is amazing. Pop that pedal down and you'll spin your tires all through 1st and into 2nd.

A lot of your decision will key on how much highway driving you do. I live and work and play in a metro area where the freeways are posted 60 mph. My drive to and from work is typically 45-55 mph. I very very seldom get out on the highway to go 75 mph for long periods. Going 55-65 with 4.10s is comfortable. 65-75 is pushing it if you have loud exhaust. 75+ is like holding it at 2800-3000 RPM for a long time. Get on the freeway and go 60 mph. Click off your OD and hold that for 30 mintes. That's what 75+ is like with 4.10s. If I have to drive on the highway for over an hour, I take a different vehicle.

Good luck with your decision.
 
My 4.10's do not spin so bad at higher mph's. I personally would go higher than 4.10's in an auto w/ a 4R70W. /shrug

And I'm sure I'll get flamed for this one but, oh well.... I barely notice a difference in acceleration with my 4.10's over the stock 3.27's. Maybe it was all the hype I was hearing about them that made me so eager to get them. Sure, I shift out of gears significantly quicker and there's a bit more mid range sotp but nothing I found to be absolutely astonishing.
 
My 4.10's do not spin so bad at higher mph's. I personally would go higher than 4.10's in an auto w/ a 4R70W. /shrug

And I'm sure I'll get flamed for this one but, oh well.... I barely notice a difference in acceleration with my 4.10's over the stock 3.27's. Maybe it was all the hype I was hearing about them that made me so eager to get them. Sure, I shift out of gears significantly quicker and there's a bit more mid range sotp but nothing I found to be absolutely astonishing.

+1

i went from 3.08 to 3.73 in my auto and I was kind of disapointed..I guess I was expecting more...should of went with like 4.56 haha...honestly...I dont see why everyone with a mustang throws gears in them...why not put 500 dollars towards a tuner or something else IMO

500 dollar xcal2 and tune on auto gt >500 dollar gears on auto gt
 
+1

i went from 3.08 to 3.73 in my auto and I was kind of disapointed..I guess I was expecting more...should of went with like 4.56 haha...honestly...I dont see why everyone with a mustang throws gears in them...why not put 500 dollars towards a tuner or something else IMO

500 dollar xcal2 and tune on auto gt >500 dollar gears on auto gt

At the track a shorter gear helps to make better your 60ft times - that's why people do it.