Rear Gear HELP!!!!

arcwcb

Member
Oct 26, 2009
417
2
19
Pennsylvania
I have a 2006 GT 5-spd that I got used (the guy only had it like 6 months before he ordered a GT500). My question is, I'm looking to upgrade my rear gears, get a little more acceleration out of the car while it's on the street. But I don't know what to go with, and to be honest, I don't even know what the car has in it stock. I still have to drive the car on the highway a lot, my college is 210 miles from home, so highway MPG is important. Is there a nice medium on gears, better acceleration without killing MPG, or is it all or nothing? Thanks for your help, ANY advice or personal opinions on this would be great!
 
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I have a 2006 GT 5-spd that I got used (the guy only had it like 6 months before he ordered a GT500). My question is, I'm looking to upgrade my rear gears, get a little more acceleration out of the car while it's on the street. But I don't know what to go with, and to be honest, I don't even know what the car has in it stock. I still have to drive the car on the highway a lot, my college is 210 miles from home, so highway MPG is important. Is there a nice medium on gears, better acceleration without killing MPG, or is it all or nothing? Thanks for your help, ANY advice or personal opinions on this would be great!

I HAVE A 2010 STANG, AND I HAVE HAD 3.31;S (STOCK) THAN 4.10'S, AND NOW 3.73'S.... IMHO 3.73 IS THE PERFECT GEAR...YES, A 4.10 GEAR WILL YIELD BETTER 1/4 MILES TIMES (IF U CAN HOOK) AND WILL BE MORE FUN AROUND TIME WITH THE EXTRA LOW MPH OOMPH, BUT I WENT TO 3.73'S FOR A FEW SIMPLE REASONS...I CAN HOOK UP *BETTER* W/ STREET TIRES ON THE STREET, AS WELL AS HAVING SLIGHTLY LONGER GEARS...ALSO, ALTHOUGH I'M SURE IM GOING TO HEAR IT ON THE FORUM FOR THIS..BUT, CURRENTLY WITH 295 35 18" REAR TIRES AND 3.73 GEARS MY 4TH GEAR @ REVLIMITER (6700) CAN STILL JUST TOUCH 140 MPH AND BURY MY NEEDLE..WITH THE 4.10'S I WOULD HAVE TO GO TO FIFTH AND THAT WAS ANNOYING...HAHA.. AND, AS FAR AS FUEL ECONOMY TO BE HONEST, I REALLY DIDNT NOTICE TOO MUCH OF A DIFFERENCE, BUT, FOR ALL AROUND GOOD EVERYTHING I REALLY RECOMMEND THE 3.73'S...ANYTHING UNDER 3.55'S IS MISERABLE, THAT MUCH I CAN TELL YOU, IT U CAN DO 50+ MPH IN 1ST GEAR..YOU HAVE 3.31'S...
 
I agree on the 3.73. I really notice the difference between my car and others that are stock. 50mph in first gear? Mine won't go over 15-20. First gear is a drag option. I can drive daily without it.
 
I agree on the 3.73. I really notice the difference between my car and others that are stock. 50mph in first gear? Mine won't go over 15-20. First gear is a drag option. I can drive daily without it.

YEAH, MY CAR (2010) CAME WITH A 5 SPEED MANUAL, 3.31 GEARS AND THE 19" WHEELS..AND KEEP IN MIND THE 2010 GT HAS A 6500 REDLINE.. SO YEAH, LOL, FACTORY STOCK I COULD HIT 50 MPH IN 1ST GEAR W/ MY 6500 RPM REDLINE, 3.31'S AND THE BIG 19'S..HAHA, THE 3.73'S AND MY NEW CHOICE OF REAR TIRE SIZE (295-35-18) MAKES THE CAR A JOY TO DRIVE, BUT NOT TO REV-HAPPY WHERE U WISH U BOUGHT A 6 SPEED TO SWAP IN..HAHA
 
So 3.73 seems to be the magic number for rear gears lol. Can anybody give me an actual number on how much it lowered their gas mileage on the highway? Just curious, because that is really the only thing keeping me from ordering them right now lol. I'm gonna be swapping out my 2-piece driveshaft for a single-piece aluminum unit at the same time, so hopefully that working with the new gears should help me rev into my torque band a little quicker.
 
So 3.73 seems to be the magic number for rear gears lol. Can anybody give me an actual number on how much it lowered their gas mileage on the highway? Just curious, because that is really the only thing keeping me from ordering them right now lol. I'm gonna be swapping out my 2-piece driveshaft for a single-piece aluminum unit at the same time, so hopefully that working with the new gears should help me rev into my torque band a little quicker.

Go with 4.10s are nothing at all. Your car already has 3.55s so 3.73 would be a waste. Don't worry about it lowering gas mileage. You bought a mustang not a Prius. With that said, 4.10s lowered my hwy gas mileage about 2 MPG. At 70-75 I get about 24 or so MPG. I drive about 50 miles per. day on the hwy, so anyone that says 4.10s are not good on the hwy are full of crap. With street tires 4.10s were a little tricker to launch at the track, but once I got use to it, I dropped my E.Ts. Best 1/8 mile with 3.55 are 8.9 and with 4.10s 8.69.
 
Go with 4.10s are nothing at all. Your car already has 3.55s so 3.73 would be a waste. Don't worry about it lowering gas mileage. You bought a mustang not a Prius. With that said, 4.10s lowered my hwy gas mileage about 2 MPG. At 70-75 I get about 24 or so MPG. I drive about 50 miles per. day on the hwy, so anyone that says 4.10s are not good on the hwy are full of crap.

thats about right, like i said, its not really too much of a loss in m.p.g.'s, about 2 mpg's sounds about right! I never said they werent good, it also depends on your horsepower and revlimiter what you want, I'm approaching the 500 r.w.h.p. mark, so the 4.10's make it a no-no for any street tire 1st or 2nd gear rolling-W.O.T. blast without magical appearing tiresmoke, lol... I loved the 4.10 with just bolt ons as a daily driver, i just do alot of VERy highspeed runs (all my friends have Zo6's n Vipers..lol) so once I got the blower I liek the 3.73s, and I can still get 140 outta 4th and god knows outta 5th... It's really all the persons personal preference, but keep in mind, mine came w/ 3.31's...lol...so the 3.31's - 4.10 was a lil rev happy for me at the time, but damn were the smokin 1st-3rd burnouts fun... but now i got boost to make up for the taller gear..haha

*8AND KEEP IN MIND I HAVE A TUNED 2010 W/ A 6700 REVLIMITER, 4.10S ON A STOCK 05-09 WILL RUN OUTTA 4TH GEAR @ 6000 RPMS MUCH SOONER THAN THE 135 MINE DID @ 6700 RPMS.. IM GUESSING 120 SUMTHIN IN 4TH..CORRECT ME IF I'M WRONG?!
 
thats about right, like i said, its not really too much of a loss in m.p.g.'s, about 2 mpg's sounds about right! I never said they werent good, it also depends on your horsepower and revlimiter what you want, I'm approaching the 500 r.w.h.p. mark, so the 4.10's make it a no-no for any street tire 1st or 2nd gear rolling-W.O.T. blast without magical appearing tiresmoke, lol... I loved the 4.10 with just bolt ons as a daily driver, i just do alot of VERy highspeed runs (all my friends have Zo6's n Vipers..lol) so once I got the blower I liek the 3.73s, and I can still get 140 outta 4th and god knows outta 5th... It's really all the persons personal preference, but keep in mind, mine came w/ 3.31's...lol...so the 3.31's - 4.10 was a lil rev happy for me at the time, but damn were the smokin 1st-3rd burnouts fun... but now i got boost to make up for the taller gear..haha

*8AND KEEP IN MIND I HAVE A TUNED 2010 W/ A 6700 REVLIMITER, 4.10S ON A STOCK 05-09 WILL RUN OUTTA 4TH GEAR @ 6000 RPMS MUCH SOONER THAN THE 135 MINE DID @ 6700 RPMS.. IM GUESSING 120 SUMTHIN IN 4TH..CORRECT ME IF I'M WRONG?!

In your case 3.73s would be a better fit. For the OP, I think 4.10s would be better unless he has plans on going F/I then I would just keep the 3.55s.
 
Just found my window sticker, it doesn't have the option for the 3.55 rear listed, so I guess I have the 3.31s. Either way, I know I didn't get a Prius, but 2-3 mpg makes a difference on a 210 mile trip back to school. I think I'm gonna go with the 3.73s, they seem to be a nice middle of the road and I haven't heard anything bad about them yet. Besides, if there is a time that they aren't enough, that's why I put the N2O on...
 
Just found my window sticker, it doesn't have the option for the 3.55 rear listed, so I guess I have the 3.31s. Either way, I know I didn't get a Prius, but 2-3 mpg makes a difference on a 210 mile trip back to school. I think I'm gonna go with the 3.73s, they seem to be a nice middle of the road and I haven't heard anything bad about them yet. Besides, if there is a time that they aren't enough, that's why I put the N2O on...

If it's an 06 manual 3.55s were standard, so it will not be on your window sticker. Look at the sticker on the axle pumpking and it will tell you what gears are in there.
 
Great chart, that really helped a lot! Will there be a noticeable difference in the cars acceleration? I'm wanting something that provides a nice snap off of the line, but is still nice to drive, not some drag star that sucks for road trips.
 
Yeah, I heard Motive gears aren't that good. I just don't want to have 4.10s in the car, I used the gear chart and even with my 20s, they still were gonna have way too high of an RPM when cruising at 70 to be used for my application. But if I won't even notice a difference when going to the 3.73s, then I'll just leave it alone and just do the driveshaft.
 
I don't think 4.10s RPMs are too high. I drive over 50 miles per. day on the hwy five days per. week. I have never once thought to myself "I wish I still had my 3.55s" In the city it's even possible to get better gas mileage with the 4.10s as it reduces the load on the car and allows it to reach the power band quicker.
 
Wait, gmantheman just said that it's not a big enough step up from stock and it's not worth it unless you go two steps up in gears... Are the 3.73s worth the money or not... I'm not going to 4.10s because I'm not gonna run that in a car I drive as far as I have to, but if the 3.73s will still give me a noticeable jump in acceleration while not affecting MPG... I'd love to hear from somebody with a 5-spd that made the jump from 3.55s to 3.73s and can attest to how much improvement there was, if any.
 
I disagree. The 3.73s work very well with a stock/mostly stock set up. I don't have any comparisons for gas mileage, because mine came with them. But, I can say it is much quicker off the line than a regular stock GT. It works for me.