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Ford Performance Ring Gear and Pinion Kit - 3.73 Gears (99-04 GT)

Market Price $164.99 You Save 9% ($15.02)
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  • Item 24001G99
  • MPN# M-4209-F373N

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Ship to: ASHBURN - 20146
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    Features & Details

    • Ford Racing Quality
    • Strong Forged Construction
    • 3.73 Gear Ratio
    • 8.8" Ring Gear Diameter
    • For Street or Track Use
    • Fits 1999-2004 GT, Bullitt, Mach 1 and Cobra Mustangs
    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 1999 to 2004 V8 Mustangs including the GT, Bullitt, Mach 1 and Cobra models. A master bearing kit is recommended by most installers, especially on high mileage vehicles, 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: 1999 2000 2001 2002 2003 2004 Details

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

    Approximate RPM for 1999-2004 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 1480 1721 2034 2347

    Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
    1 3267 4573 5880      
    2 1783 2496 3209 3922 4636 5349
    3 1150 1610 2070 2531 2991 3451
    4 805 1127 1449 1771 2093 2416
    Will it fit my Mustang?
    • Bullitt - 01
    • GT - 99, 00, 01, 02, 03, 04

    People Who Bought This Item Also Bought

    Most Helpful Reviews

    3.73 gears

    My son got me the gears for fathers day.... just had them installed,all I can say is hold on to your seat!!!! 2nd and 3rd will set you back in the seat,easy to install,be careful when you change out the ...

    Read More
    Helpful (15)

    04GT 3.73gears

    DONT FEAR THE GEAR! The perfect gear for a street car. Decent RPMs on the highway and crazy excelleration through first 3gears. Have them installed by an experiance tech who has done these before. Its ...

    Read More
    Helpful (7)

    Overall Rating 4.8 out of 5 stars
    Read All 85 Reviews

    Customer Photos (6) Submit Your Photo

    View All 6 Photos

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    10 Questions / 8 Answers

    Ask a Question

    Hi. I've got an auto 2004 conv GT. I've purchased from AM: the Pypes Violator Cat Back System, and the SR CAI. I've upgraded the COPS to Accel as well. I'm thinking about getting these gears and a Bama Tuner. I've also removed the 2 rear cats, leaving the front two cats with O2 sensors in place. What kind of performance gains can I expect? Car has only 68,000 miles. Thanks!


    • The Bama tuner will help add power to everything you have going on right now for sure. It would be tough to give a specific number considering the mods you have already going on, but if you contacted Bama directly they could give you a good estimate based on your mods. As for the gears, this is a mechanical change as opposed to a performance change so the gears aren't going to give you any true gains. However, an upgrade in your gear ratio allows you to reach the top end of each gear much quicker, resulting in a quicker 0-60 time.


    Helpful (0)

    Okay, so kinda new to the whole modding venue but I have heard good things about changing gears out. So here is my question, as a newbie, how many gears do I need to purchase and what other items to get them up and running for my bone stock 2003 gt auto? Thanks!


    • Hello! The following kit will have everything you need to get your 03 GT up and running with new gears: In order to re-calibrate your speedometer, we recommend getting a handheld tuner like the Bama X4


    Helpful (0)

    Will these gears be good for stage 4 comp cams? Want power but also want decent MPG. Also do I need a whole new differential? My mechanic said it'd be smart to do and it'd be more cost in parts but less in labor?


    • 3.73s are your best bet to compensate for the camshafts but still have your drivability. As far as needing a new differential? That depends on how soon you think/your mechanic thinks your current differential will need to be replaced. Basically, if your current differential is beat up, replacing it now will save you time and money from needing to do it later, considering you are already down there to put the 3.73s in.


    Helpful (0)

    I have the 4.10 ford racing gears on my car and i was thinking about getting the 3.73 gears, would i still have to buy the install kit or would the previous kit still work?


    • We would recommend replacing all the bearings and seals when you swap out the gears. If your seals and bearings are still very new you could get away with out doing them again.


    Helpful (0)

    Good for boost? I have a 2000 mustang gt convert, i plan on boosting somewhere down the line but im worried that all ill do is spin even with a full suspension set up, would you guys recommend these gears or the 3.55's?


    • 3.55 or even 3.27 would be better. With a boosted car you want a slightly longer gear for better cylinder filling throughout the gear and to control torque transmitted to the tires.


    Show 1 more answer Helpful (0)

    Traction-LOK rebuild kit Is the traction-LOK rebuild kit necessary when you change out your gears? What exactly is it for?


    • While not necessary, it would be recommended. It's a rebuild kit to redo your limited slip. The piece that makes both of your wheels spin when you do a rebuild.


    Show 1 more answer Helpful (0)

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    Customer Reviews (85) Write a Review

    Overall Rating 4.8

    out of 5 stars

    Installation Time:Weekend

    Installation Cost:$250-$500

    • Performance Gain 4.484848 4.5
    • Fit 4.764706 4.8

    • 5/5

      June 14, 2011

      3.73 gears

      My son got me the gears for fathers day.... just had them installed,all I can say is hold on to your seat!!!! 2nd and 3rd will set you back in the seat,easy to install,be careful when you change out the ABS rings they brake easy. Thanks again son.

      Ronald Peagler

      Year: 2003 Submodel: GT

      Helpful (15)

    • 5/5

      April 05, 2010

      04GT 3.73gears

      DONT FEAR THE GEAR! The perfect gear for a street car. Decent RPMs on the highway and crazy excelleration through first 3gears. Have them installed by an experiance tech who has done these before. Its hard to keep my foot out of it now!

      Dickie Ayer

      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 (7)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      August 14, 2012

      Bye bye

      I had a moan and drone at 2000 RPM coming from my Flowmaster mufflers prior to installing these gears. I installed these gears and the drone disappeared because the motor was working with greater ease at this and all RPMS. I installed them to increase my performance and got this as an added bonus. My intake and exhaust modifications are now maximized using these gears in conjunction with my custom tune. I never used my street tune prior to installing these gears but actually wanted to tone things down a little for my daily drive. I cannot believe that I just said that but it is true.


      Year: 1999 Submodel: GT

      Helpful (6)

    • 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 (5)

    • 5/5

      February 08, 2011

      02 MUSTANG GT

      Just had these beasts put in. They have an amazing difference i had them done professionally by gambardellas racing in williamstown nj they did a excellent job for only 250. the speedo is up 7mph for the 02 mustang gt with the tr3650 tranny so its not a big deal. thanks am you guys are the best!


      Helpful (5)

    • 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 (5)

    • 5/5

      October 13, 2010

      Good buy for any guy (or gal)

      Bought gears, install kit, and girdle a few weeks ago and had them professionally installed. Very happy with the gears and how well my car pulls now. If you want to make your car a little quicker without major cash, these gears are an excellent choice.


      Helpful (4)

    • 5/5

      August 14, 2010

      3.73 2004 mustang gt

      I bought these a while and just ha the money and time to put em in by a professional today and felt the difference. Best buy for a daily driver and whatever else you wanna do. I couldnt help keep my foot off


      Helpful (4)

    • 4/5

      July 02, 2010

      99 Cobra

      I put these in my 99 Cobra about a month ago and they really didn't make a difference from the stock 3.27 except for lil worse gas mileage. These gears kick great in GT's and are good for daily driver Cobras but if ur lookin for a good punch in a 4V Cobra u need steeper gears cuz of the 7k redline. o and the pinion broke a week ago :(

      Kyle S.

      Helpful (4)

    • 5/5

      April 30, 2010


      I bought these for my 2003 GT 5spd with the TR3650 and it is a new beast! It is very quick from a stop now and should shave 3 tenths or so off your 1/4 mile time, gas mileage wasnt really affected in fact it improved a little because I drive a lot in the city at speeds around 35-50mph and rarely go over 85mph so if you drive in the city and the highway at speeds around 75mph @ 2200rpms you will get about 21mpg. The gears have a little decel whine in 3rd gear but it isnt bad at all. Be shure to buy the Motive bearing kit when you do the install or you will regret it and I got mine installed for around 300 bucks at a local shop.


      Year: 2003 Submodel: GT

      Helpful (4)

    • 5/5

      March 18, 2010


      Had the 373 installed in my 2000 GT convt and the whole rear end trac-loc rebuilt with carbon clutch packs. WOW! The beast just pulls harder and harder as that retach goes. The carbon clutch packs does wonders for putting the power down on the pavement, it just catapults the car from a dead stop or on the go. Best money spent so far on the upgrades. Just order BBK shorty headers to attach to the SLP Hi-flo X-pipes. Can't wait to have them installed!!


      Helpful (4)

    • 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 (4)

    • 5/5

      Installation Time: Afternoon

      September 15, 2011

      This product is a must have if you own a mustang! more power, more torque, more accelaration, more get up n go off the line not sluggish anymore!

      I had these gears installed by my mechanic professionally and I gotta say what a diffrenence the gears made! great off the line power and you will enjoy 1st 2nd and 3rd gear!!! makes your engine sound nice as the rpm's are now higher then before. i was on edge for weeks on what gears to go with 3.73 or 4.10 so i did my homework and went with the 3.73 very happy with my purchase thanks again AMERICAN MUSCLE!!!


      Year: 2000 Submodel: GT

      Helpful (3)

    • 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 (3)

    • 5/5

      April 13, 2009


      Finally installed the 3.73\'s on my 03 GT and all i can say is WOW. Talk about a great item to get you out of the dig.


      Helpful (3)

    • 5/5

      May 23, 2008

      Need For Speed

      These 3:73 gears are awesome. Ford should have built mustangs with these gears instead of the whimpy 3:27\'s. Be prepared to get whiplashed while switching through gears. And if your good with the stick (manual transmission) you can burn rubber in 3rd gear too. These gears unleashed the beast within my 03 mustang they are a must have.


      Helpful (3)

    • 3/5

      July 11, 2011

      373 gear swap

      Mine is a 5-spd GT Conv- which is slightly heavier, so maybe that's why I did not get the blistering performance gains that many of the other posters here describe. It was definitely noticeable, but I was slightly disappointed after reading the other posts. I will say it's probably a good compromise though as the RPMs at 75 are still reasonable (somewhere around 2550 or so). AM's speed and service however were excellent as always..

      M. Lemon

      Year: 1999 Submodel: GT

      Helpful (2)

    • 5/5

      April 09, 2010

      Can you say IMPROVEMEMT?

      Installed on my 03 GT. Install price was $200 trust me if you dont know what you are doing with the shims and setting the backlash have a pro install these, but lauch is much improved 2nd gear is nasty. Went to the local strip with is an 1/8 mile track and ran 9 flat with the help of the AM CAI. Killed a few Comaros in the process and isn't that what we are all after? Buy it stop reading! GO!

      Matt D

      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)

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