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Ford Performance Ring Gear and Pinion Kit - 3.73 Gears (05-09 GT)

Market Price $164.99 You Save 9% ($15.02)
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  • Item 24001G05
  • MPN# M-4209-F373N

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Features, Video & Details

  • Ford Racing Quality
  • Strong Forged Construction
  • 3.73 Gear Ratio
  • 8.8" Ring Gear Diameter
  • For Street or Track Use
  • Fits 2005-2009 GT, Bullitt and GT500 Mustangs

Review & Installation Video

Review & Install Video

Hey, guys, Stephanie with here with these Ford Racing 3.73 gears for all Mustangs with an 8.8 rear or '86-'14 V8 and 2011-2014 V6 Mustangs. Gearing's really important to a car, and it can make or break a build no matter how much power you may or may not have. Gears should be carefully chosen based off your intentions and the performance that you want out of your car. These 3.73 gears from Ford Racing are gonna be a good option for those of you out there that aren't wanting to spend a ton of money, but that are looking for a good gear that will perform well for a daily driver and for the car that might see the track occasionally. I would say that the 3.73 gear is a middle of the road option. It's short enough to provide a huge difference in driveability, but not so short that it'll create a negative impact on street driving. When you go about choosing your rear gear, you'll have to keep in mind where and how you mostly drive your car. You do a lot of highway driving, you aren't going to want a short gear, and if you're looking for acceleration improvements from a stop, you aren't going to want a tall gear, either. A 3.73 gives you a little bit of both worlds here. You'll get a cruise on the highway without screaming in those higher RPMs, but you're really going to notice a big change in acceleration as well and that's what makes these good for a daily driver. If you're coming off of stock gearing and you're moving into a 3.73, you're going to think that you're driving a totally different car because the gears are gonna totally change the driving experience. Even if you have some bolt-on mods already, your car probably still feels sluggish but it won't after the gears are installed. If we break this down some, the basic way that rear gears work can be boiled down to saying that the number of the gear is how many times the drive shaft will turn to one turn of the rear wheels. So in this case, the drive shaft will turn 3.73 times for every one turn of the rear wheels, and this is how such drastic changes in the driving experience are made. Typically speaking, low gears give higher top speeds and better fuel economy, but the tradeoff there is a car that's slower off the line with less torque. High gears, on the other hand, are the exact opposite and the 3.73s hear fall in the middle, and they're a great all-purpose type of gear. A set of gears includes a ring and pinion gear and Ford Racing gears a forged gear that are CNC cut with lapped gear teeth. These also have a black oxide finish, so that'll help resist corrosion, and in case you happen to be worried about it, these are not a noisy gear so don't expect a lot of whine with these. Upgrading rear gears will throw off the calibration of your speedo no matter which brand you end up choosing. It's just a side effect of choosing the ratio, but Ford Racing does make a recalibration tool to fix this issue, so just keep that in the back of your mind. Or the issue can be fixed with a tuner, as well, but if you don't happen to already have a tuning device, then the recalibration tool is going to be a less expensive way to fix it. As far as price, these gears are going to be the least expensive that are available on the site, costing under $150. There are some other brands to choose from but they're gonna be more expensive, and I did want to mention that you should also pick up a gear install kit while you're purchasing these. The price of this kit is going to change depending on if you want just the install kit or an install and bearing kit, but you're looking at an additional 30-75 bucks for either one of these. And depending on the mileage and the last service, it could also be a really good idea to invest in entirely rebuilding the rear while it's apart, but that's up to you. So I'm not gonna say that the install here is easy because it's not. You're looking at taking the car to a shop for a proper install or having a nice collection of tools since you will need a handful of items and about four hours to get the job done yourself. This is a three out of three wrenches on the difficulty meter. This is a pretty big project that's going to require removing the axles, which means dropping the driveshaft, the rear brakes, the diff pinion shaft, and the axle shaft U-washer, and you've got to remove the differential itself, which means removing the diff bearing cap bolts and the shims, which all needs to be marked and reinstalled the same way. The assembly and install of the new gears is very specific, and I'm obviously giving you guys a general overview here, so I'll just mention that you'll need to check for diff case run out as well as check pinion depth and do some shimming, as well. Then you've got to get it all back together after measuring and checking your work over. Wrapping things up here, the Ford Racing 3.73 Gears for the 8.8 rears are a great gear for cars that see a lot of street time and some track time. They're a middle of the road gear that offers the best of both worlds when we look at the benefits of a tall gear versus short gear, and they're the most affordable gear set on the site. They are CNC cut and they have lapped teeth, and you can check them out more online right here at

Improve ET's and low end torque. Are you looking to get more low end grunt off the line and lower ET's at the same time? Then look no further than installing a set of steeper gears in your Pony. Ford Racing Ring and Pinion Gears are perfect for street, road, or race use.

Superior Quality. These Ford Racing 3.73 Mustang ring and pinion gears feature a super strong forged construction, CNC cut & lapped gear teeth, and a black oxide finish to resist corrosion.

Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a Ford Racing Speedometer Recalibration Tool is an inexpensive way to fix this issue.

Application. This Ford Racing Ring and Pinion Gear set will fit all 2005 to 2010 V8 Mustangs including the GT, Bullitt and GT500 models. A master bearing kit is recommended by most installers, especially on high mileage vehicles, see drop down option above.

Attention 2010 and newer Mustang Owners. Starting in 2010 Ford changed the inner rear gear pinion bearing in all 8.8" equipped Mustangs. Because of this you will require a new 8.8" rear gear pinion bearing (Ford part# 9L3Z-4630-A) for proper installation, please see drop down option above.

Technical Note. Installation costs will vary, but a good rule of thumb is between $250 and $300. Be sure to work with a reliable shop that you trust for installations. You can also save money on your installation labor by having your Trac-Lok rebuilt at the same time as your gears are installed, see drop down option above.

Fitment: 2005 2006 2007 2008 2009 Details

What's in the Box
  • (1) Ring gear
  • (1) Pinion gear
Installation Info
Tech Specs

Approximate RPM for 2005-2010 GT

Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
1 3888 5443 6998      
2 2301 3221 4141 5061 5981 6902
3 1518 2126 2733 3340 3948 4555
4 1150 1610 2070 2531 2991 3451
5 782 1095 1408 1721 2034 2347

Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
1 3704 5185 6667      
2 2634 3688 4741 5795 6849  
3 1771 2480 3189 3897 4606 5314
4 1150 1610 2070 2531 2991 3451
5 817 1143 1470 1797 2123 2450
Will it fit my Mustang?
  • Bullitt - 08, 09
  • GT - 05, 06, 07, 08, 09
  • GT500 - 07, 08, 09

People Who Bought This Item Also Bought

Most Helpful Reviews

Great improvement for your stang

I know the easiest way for me to have great low end was to buy gears. I choose 3.73 beacse my stang is also a daily driver. I am 18 years old and a mechanic at ford. This took me 1 hour to install. And ...

Read More
Helpful (13)

Perfect with Cams

I recently added FRPP hot rod cams in my 08 automatic mustang with 3.31 gears. It was almost impossible to drive slow around town, the car would buck and jerk and i lost almost all low-end power as the ...

Read More
Helpful (7)

Overall Rating 4.8 out of 5 stars
Read All 65 Reviews

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8 Questions / 10 Answers

Ask a Question

if i have my local ford dealer install these can they calibrate my speedometer?


  • I would suggest calling your local Ford dealer to check and see if they will install the Ford Performance 3.73 Gears and if they can calibrate your speedometer as well although I do not believe they can recalibrate the stock tune for larger gears. I suggest using the Ford Performance Speedometer Recalibration Tool ( which can be found here: ) to properly recalibrate your speedometer after you get the 3.73 gears installed.


Helpful (1)

So I've heard both ways. You get gears, you NEED a tune. You get gears, tune isn't necessary. I would like to buy these gears and get them installed. But do I really NEED to tune it afterwards? And if I don't, what are the consequences? Please if y'all could help me out.


  • When installing these, you will absolutely need a new tune and that would to correct the speedometer and make sure that the vehicle gets the best performance with the upgraded gear selection you have. If you do not get your vehicle re-tuned, your vehicle will not be aware of the difference in the gear which will cause problems with your RMPs and your speed will not accurately displayed on your dash.


Helpful (0)

Is a tuner necessary to correct the Speedo after gears or can a dyno shop correct the speedo without a tuner?


  • A S197 does not have speedo gears and will need a tune to correct the speedometer.


Helpful (0)

Hello guys, I recently had this set of gears installed and I've completed my break in period so now its time for the gear oil change. I am wondering it if would be best to go with 75w140 oil which is what the stock gears used on the 08 Stang. I know the gears come with 75w90 but ford had a TSB where they changed all there oil to 75w140 due to complaints of rear end noises.


  • The Ford Performance 3.73 Gears (05-09 GT) would work very well with what the stock oil weight. The 75w140 would be great to use on these gears.


Helpful (0)

i want to go without a tune or recalibration tool would that work out or would it effect my engine ? and can i go only for the gears and get the other parts later ?


  • The Ford Performance 3.73 Gears (05-09 GT) will not require the use of a tune or recalibration tool to run properly. However your speedometer will be off with out using one of the two options above.


Helpful (0)

What gains will I notice in my 07gt500? I know the KR and super snake came with a 3.73. What will I notice changing from a 3.31? I have an 07 gt500. I realize it came with a stock 3.31. I know the gt500KR and the Super Snake came out with 3.73. What awe the advantages of the change?


  • Yes you will. I changed from 3.55 gears in my 07 GT to Ford Racing 4.10 gears and it really woke the car up!! Much quicker off the line and little to no difference in gas mileage.


Show 4 more answers Helpful (0)

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Customer Reviews (65) Write a Review

Overall Rating 4.8

out of 5 stars

Installation Time:Weekend

Installation Cost:$250-$500

  • Performance Gain 4.814815 4.8
  • Fit 4.851852 4.9

  • 5/5

    Installation Time: Less than 1 Hour

    October 09, 2011

    Great improvement for your stang

    I know the easiest way for me to have great low end was to buy gears. I choose 3.73 beacse my stang is also a daily driver. I am 18 years old and a mechanic at ford. This took me 1 hour to install. And if you do everything right you wont hear any noise. I didnt need to use the shims that came with the kit becase the pinion depth is set by the factory. I also used the old pinion bearing from the factory pinion. and if you guys ever want to use a new bearing dont just install the bearing and not install the race. Cuz ford redesign the bearing and the factory race is way bigger than the redesigned. Backlash was not an issue for Me. Everythin fit right and i dont hear any noise at all from the new gears. Now i crush ls1's with simple bolt ons.


    Year: 2005 Submodel: GT Arlington, VA

    Helpful (13)

  • 5/5

    Installation Time: Afternoon

    June 09, 2012

    Perfect with Cams

    I recently added FRPP hot rod cams in my 08 automatic mustang with 3.31 gears. It was almost impossible to drive slow around town, the car would buck and jerk and i lost almost all low-end power as the cams like to keep the car in higher gears. Well after installing the 3.73 gears my car run AMAZING. Good low end power for driving around town and getting off the line but the mid-range power is where the car really comes alive and doing 80 on the highway my car is at 2500 rpms. My car is now a beast and I recommend these to anyone installing cams who drive their car daily. They're perfect!


    Year: 2008 Submodel: GT NJ

    Helpful (7)

  • 5/5

    October 24, 2009


    Wow these gears amazing. I have an automatic and these gears made a HUGE difference. Thank you Ford Racing and American Muscle.


    Helpful (5)

  • 4/5

    Installation Time: Full Day

    August 29, 2011

    Great bang for the buck

    The installation took me about 8 hours because the darn thing refused to shim out correctly. And even when I got the marks looking perfect on the gear I still have a whine on coast side between 45 and 55 mph. I've gotten used to it. Apparently some of it comes down to the cut of the gear. Ford RACING is meant for just that racing. They do not cut the gears for being quiet. So it is very hard to avoid some sort of whine after install.


    Year: 2006 Submodel: GT Exton, PA

    Helpful (4)

  • 5/5

    April 14, 2010

    Gears, Gears

    Don't fear the gear is correct. I couldn't of said it better. Gas shouldn't be a factor when your driving around in a V8 it's obvious.To those who are concerned don't be. I was too and I must say it was worth the labor. Gas mileage is nothing compared to what you get out of these. If you like to go faster...faster then swap your stock ones for these. I did and already I am regretting not getting the 4:10's. 1st and third never felt better.Thanks AM


    Helpful (4)

  • 5/5

    July 18, 2009

    FRPP 3.73

    These gears are perfect for my combo, they now sit behind a 450+hp engine and holding fine.

    Jeff Bailey

    Helpful (4)

  • 5/5

    Installation Time: Shop Install

    April 17, 2012

    Great upgrade

    I bought these gears for my '07 Gt (5 speed) with 3 goals in mind. 1: Increase performance 2: reduce my excessive highway cruising speed 3: reduce or eliminate a drone from my axle back exhaust My shop did the installation and there is absolutely no noise from these gears. I re calibrated the speedometer with my Diablo tuner in 5 minutes and corrected the 10 mph error from the new ratio. The exhaust drone that I had on the highway from 60 to 70 mph is totally gone and I no longer find my speed creeping up to escape from the noise. My fuel economy as calculated by the cars computer is 25.5 mpg with the cruise control set to 68 mph. ( I have a C&L cai, Diablo 93 octane tune, under drive pulleys and Ford Racing axle back exhaust). Creeping in slow traffic is easier now and top gear acceleration from 70 to 100+ mph is more impressive. The 3:73 gears really compliment my engine and suspension mods. Yes l like to blast through the gears but I don't need to cruise at 80 anymore to enjoy the sound of the axle back stingers. Mission accomplished!


    Year: 2007 Submodel: GT Ct.

    Helpful (3)

  • 5/5

    Installation Time: Less than 1 Hour

    February 07, 2012

    Respect the Throttle

    I spent a lot of time mulling over whether or not to make this investment. After consulting the pros and cons of swapping the rear gears, I pulled the trigger. Cost me $350 for installation from West Coast Ring and Pinion in Rancho Cordova, CA. The question I had after deciding to do it was whether to go 3.55 or 3.73. I have too much highway driving to justify 4.10’s, as the RPM would just have the engine singing too much. After discussing the issue with West Coast, I went for the 3.73's. West Coast did not have the flash tuner to correct the speedo and shift points, but assured me no damage would occur from a rear end swap. I will have the annoyance of having to do the math all the time, but that is about it. As far as shift points go, I find no difference. The automatic seems to shift out at the same points under WOT sprints. Now, in mild driving, it does shift up quicker, but that is about it. The car snaps off the line, stands on its tail at any speed I mash the pedal and just makes the ride even more exhilarating. So far the gas mileage hasn’t been affected much. It dropped some highway miles by about 2-3 on long 75-80mph interstate runs (was about 24-25 and now about 22-23), but the city mileage has pretty much remained the same (hard to gauge with all the sprinting vs. mild mannered mix) The problem I gotta fix now (besides the speedo correction) is the pronounced rear squat. The snap is that much more over the 3.31’s that the rear pushes down even harder, which is annoying. It is a pain to have to drive by RPM. According to a roadside radar display, looks like I am off nearly 10mph now.


    Year: 2006 Submodel: GT Loomis, CA

    Helpful (3)

  • 2/5

    November 02, 2010

    Bad Alignment

    The gears appeared to be well manufactured, but after trying 24 shims to 56 shims in order to get them to align properly, it was evident that they would never work without producing whine or chipping teeth. I have also installed 3.90 gears on another Mustang with no problem whatsoever; I'm buying Motive gears tomorrow because I trust them a good bit more. I recommend not buying these gears unless you know of some way to keep the teeth from not chipping when the gears will only align at the outside rim. I personally don't feel comfortable with the cruddy alignment I had. Also, beware of putting the gears on your car. Just by rotating the gears after putting them in my gear box to see the wear pattern in the paint, I voided my ability to get a refund from AM. I've had other good products from AM, but unfortunately, this isn't one. I recommend Motive.


    Helpful (3)

  • 5/5

    June 19, 2010


    This is an awesome product at an even better price, Will turn your car into a rocket, Bearing kit is the same as factory, grate quality and very tough!!!! Thanks AM!!!

    2002 GT

    Helpful (3)

  • 5/5

    September 11, 2008


    Just what my car needed. Combined with my supercharger, I can really feel the torque. 3.73s are the way to go.


    Helpful (3)

  • 5/5

    May 11, 2011

    3.73 ford gears

    these gears are a must nice and quiet nice rpm on high way ihave been rebuilding transmissions and installing gears for over 20 years and these are the best gears out there just make sure your pinin depth is correct and your back lash is set correct and these will last a long time .

    craig harkness

    Year: 2006 Submodel: GT

    Helpful (2)

  • 5/5

    February 21, 2011

    pretty good gears

    Meh, they are ok, I should have gone with 4:10's but they will do for now, acceleration did increase, but I was expecting a little more ooomph


    Helpful (2)

  • 5/5

    February 15, 2010

    !!!!!! HOLY SH*T !!!!!!!!

    Put on hot rod cams and had to change my gears for the cmas... since its my daily i put in the 3.73's...... from 3.55... OMG what a difference.... its like my car went from ... wow that prety fast to..."HLY F*CKIN SH#T" best performance mod fo the buck hands down!!!!!


    Helpful (2)

  • 5/5

    February 21, 2009


    3.73 gears woke my 2006 Mustang up in a huge way. There good for both everyday driving and burning up the track!!!


    Helpful (2)

  • 5/5

    August 09, 2008


    These gears simply wake up your car. its just so much more fun to drive now. Noticeable gains in acceleration throughout all gears. Just make sure you have a reliable mechanic do the install.

    Andy M.

    Helpful (2)

  • 4/5

    November 21, 2007

    respectable product

    My first mod, and I can feel the difference.. and not to mention a lot cheaper than other web sites!!!!


    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    October 02, 2012

    Best money I ever spent

    This should have been my first mod. A gear with a Bama 93 octane tune iIt's a beast down low more torque. Better gas milage in town and no gas neccessary to leave a green light. All you do is slowly let the clutch and and roll don't even hit gas unless you want too :D.


    Year: 2007 Submodel: GT Bloomington, IL, USA

    Helpful (1)

  • 5/5

    December 13, 2009

    Dont Fear the gear!

    What a difference!. car actully pulls hard like a V8 should..if i was to do it over again prolly would have went 4.10's but 3.73 are a great daily driver gear...still love the 3.73's


    Helpful (1)

  • 5/5

    August 15, 2009

    Great drivability

    Tore up a 3.90 ratio set and put this instead! In my opinion felt better! Did not lose the top end like before!

    Josh Hastings

    Helpful (1)

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