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

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  • Item 24001G99

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Ship to: Ashburn - 20149
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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

    MPN# M-4209-88373N

    CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

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

    Approximate RPM for 1999-2004 GT


    Manual
    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


    Automatic
    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?

      Customer Photos (6) Submit Your Photo

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        Questions & Answers (11)

        5 Top Rated Questions

        top speed yes i was wondering about top speed from these gears, I know that 4.10 gears stop you about 140mph, what does the 3.73 top you out at

        • It depends on the transmission. I have a 5 speed and my top end is good to 150 @ 6,800 rpm.

        Helpful (1) Show 1 more answer

        How bad do the 3.73 gears throw the speed off? By how many miles?

        • Upgrading your factory gear to a new 3.73 gear will generally throw your speedometer off by about 4-5 mph. You can choose to correct the speedometer with a calibration tool or by having the vehicle tuned with the new gear.

        Helpful (0)

        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: http://www.americanmuscle.com/373-gear-oil-kit-8609.html 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)
        Post Your Question
        6 More Questions
        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? 1 answer
        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? 2 answers
        Traction-LOK rebuild kit Is the traction-LOK rebuild kit necessary when you change out your gears? What exactly is it for? 2 answers
        Shop vs Self Install Is it worth it to pay a shop to install them? Or would I be able to do it myself without an issue? Also if someone could give me a rough estimate of what they paid a shop to install them for, it would be greatly appreciated. 4 answers
        Going long distance with gears I drive a 600 mile round trip for off weekends. Will this work for my car? 2 answers
        Do I need anything else? Is anything else recommended when buying a new set of gears? Bearing kit, etc..? 2 answers

          Customer Reviews (92) Write a Review

          Overall Rating 4.8

          out of 5 stars

          Installation Time:Weekend

          Installation Cost:$250-$500

          • Performance Gain 4.55 4.6
          • Fit 4.804878 4.8



          • 5/5

            Installation Time: Shop Install

            January 14, 2019

            Ford Racing 3.73:1 rear axle gears

            I just had a set of 3.73:1 installed in my 03 Mach 1. As most people know the DOHC 4.6 loves to rev, so with these new gears in stalled I get the car into higher RPM's quicker. This is a modification I would recommend for any Ford Mustang owner.

            CalvinS

            Year: 2003 Submodel: Mach 1

            Helpful (3)

          • 5/5

            Installation Time: Afternoon

            November 22, 2018

            Good choice

            Should have been one of the first things done. Well worth the money. Ford racing product are great. Within or above OE spec. Installed on a tremec 5 speed coupe. Good off the line and through the revs. Highway speeds only saw a few hundred rpm increase cruising at 70 mph. If your in there, done it all at once. Lsd clutch packs, axle bearings and seals etc.

            GregT

            Year: 2001 Submodel: GT

            Helpful (4)

          • 5/5

            Installation Time: Weekend

            October 01, 2018

            AWESOME

            Kit has everything you need, but I ended up buying a new pinion bearing to go with it.

            MontyR

            Year: 2000 Submodel: GT

            Helpful (4)

          • 5/5

            Installation Time: Full Day

            June 05, 2018

            Must have

            This kit has everything needed to do it right the first time.

            JoshuaH

            Year: 2004 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            March 31, 2018

            Great investment

            Installed these gears on my old 2002 Mustang GT. Nothing but good things to say about this gear ratio. Woke the car up and made a noticeable difference all around with highway and city driving. Honestly should have been the first mod I did to my car.

            GregR

            Year: 2002 Submodel: GT

            Helpful (6)

          • 5/5

            January 20, 2018

            373 gears

            I can tell the difference soon as i pulled off from getting them installed very happy and satisfied

            DerickR

            Year: 2001 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            January 16, 2018

            Professional Installation Recommended

            I'd tried to install a similar set previously, but the fit wasn't correct, despite hours of measuring. With professional installation, the drivetrain feels solid, and the 3.73 really wakes up the acceleration. Highly recommended.

            Crewwolfy

            Year: 2002 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Full Day

            November 26, 2017

            What gear to choose?

            Mach 1 came stock with 3:55. Not a bad choice. I purchased this Mach1 with 4:10 fun on the street first gear extremely short and with stock 17" tires I would top out and get driven around everytime at the 1/4 mile track. Felt like I needed to grab 5th gear. Switched to the 3:73 much better all around ratio. Actually improved my trap speed much more streetable. You really need to do your math and figure out what your wanting. For stock or nearstock tires size in my opinion best all around gear. I also rebuilt complete rear end.

            DavidR

            Year: 2003 Submodel: Mach 1

            Helpful (8)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            June 14, 2017

            Fantastic

            The best add on I have done so far a must have. Will make it feel like a different car and with other mods its insane.

            ZavierL

            Year: 2002 Submodel: GT

            Helpful (7)

          • 5/5

            Installation Time: Shop Install

            May 11, 2017

            3.73 gears

            If you have a standard I would highly recommend going with 3.73's. I was debating between them and 4.10 gears. I'm very happy with my decision. My Stang pulls so much harder and smoother now through every gear. Highly recommended......

            JoseG

            Year: 2000 Submodel: GT

            Helpful (7)

          • 5/5

            Installation Time: Weekend

            April 04, 2017

            Greatt!!!

            Love the 373 gears on my mustang and the shipping reacived my gears right away great product american muscle

            Flash22

            Year: 2000 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            November 19, 2016

            glad I finally did it

            I finally got these gears installed along with a rebuild kit for my rear end along with Differential track rebuild kit I am very pleased with the way everything came out my mechanic did an excellent job costing me about $400 all together for a rear end job new gaskets evt.Find yourself a good mechanic and I think these installs will be a little less Heart-wrenching on the wallet

            jason

            Year: 2003 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            June 10, 2016

            Ford 3.73 gears

            The are amazing. I daily drive my car so I still need decent fuel economy but still need enough power to keep it fun. 4.10's are great but the 3.73's seem to be just right for what I needed. The install was straight forward, I work at a shop so that helps, you'll need shims and a pinon seal if you want the job done right. I would highly recommend a professional install because you need a bearing press. They are a great product and are absolutely worth the money.

            Spartan742

            Year: 2000 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            May 17, 2016

            Great bang for the buck

            I had these gears installed into my otherwise stock 2002 GT. I also installed a Bama X4/SF4 tuner at the same time. The gears and tune really seemed to bring my GT to life. I am very pleased with the purchase.

            Dave

            Year: 2002 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Full Day

            May 07, 2016

            3.73 gears

            I was always a little skeptical about upgrading my gears. But I finally pulled the trigger since my stock ones were worn out. I have to say 3.73s are perfect. . . it takes so much less effort to get the car moving! Therefore it doesn't jerk around at a stopping start. Plus it doesn't take as many RPMs to get it moving. Yeah you have to shift a little more, but it pulls so much more aggressively!!! I never realized how sluggish 3rd gear was until I took out the stock gears and put in the 3.73s! They definitely make 3rd a lot more responsive and pull harder!

            JoshR

            Year: 2000 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Full Day

            April 18, 2016

            AM does it again

            Took my mustang to the track after installing my new gears and it feels like a new car. Everything I buy from AM fits and works just as it should.

            Stangthang

            Year: 2002 Submodel: GT

            Helpful (5)

          • 4/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            March 09, 2016

            3.73 gears

            Expensive to get installed but could definitely tell it had 3.73 gears, car just felt lighter under acceleration

            99stang69

            Year: 1999 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            December 21, 2015

            awesome product

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

            EJ

            Year: 2001 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            November 24, 2015

            Like a new car ... Then again it was installed with a new T56 Magnum 6 speed

            These 3.73s were installed with a new T56 Magnum in my 01 Bullitt GT ... Gears should be on the top of your mods list. Depending on your horsepower level you should select the right gear and for me at about 400 hp 400 trq the 3.73s are perfect with the new T56 Magnum. Gears are perfect and SILENT ... Properly installed there should be zero noise coming from your rear diff. Thanks AM

            Bullitt3055

            Year: 2001 Submodel: Bullitt Dubai

            Helpful (5)

          • 5/5

            Installation Time: Shop Install

            July 05, 2015

            good product

            have a 4.10 because of a 7.5 to 8.8 rear axle swap, i done a complete refresh to the axle including bearings and seals, want to change the gears because high rpms on highway, the 3.73 does the job doing moderate rpms at highways, and good high rpms on the track

            LuisH

            Year: 1999 Submodel: GT brownsville tx

            Helpful (5)

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