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

Item 24001G99
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      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • 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 -


      Customer Reviews (93)

      Write a Review

      Ratings Summary

      4.8 out of 5 overall rating from 93 customers

      Installation Time: Weekend

      Installation Cost: $250-$500

      • August 11, 2019

        4 2001 GT - MiguelH Installation Time: Shop Install Installation Cost: $100-$250

        3:73 Gears

        Gears work find. Definitely a little more get up to it. Have 315 in the back so I usually grab pretty well and accelerate a little quicker than without the gears

        Helpful (0)
      • January 14, 2019

        5 2003 Mach 1 - CalvinS Installation Time: Shop Install

        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.

        Helpful (3)
      • November 22, 2018

        5 2001 GT - GregT Installation Time: Afternoon

        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.

        Helpful (8)
      • October 01, 2018

        5 2000 GT - MontyR Installation Time: Weekend


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

        Helpful (4)
      • June 05, 2018

        5 2004 GT - JoshuaH Installation Time: Full Day

        Must have

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

        Helpful (6)
      • March 31, 2018

        5 2002 GT - GregR Installation Time: Shop Install Installation Cost: $250-$500

        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.

        Helpful (6)
      • January 20, 2018

        5 2001 GT - DerickR

        373 gears

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

        Helpful (6)
      • January 16, 2018

        5 2002 GT - Crewwolfy Installation Time: Shop Install Installation Cost: $250-$500

        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.

        Helpful (6)
      • November 26, 2017

        5 2003 Mach 1 - DavidR Installation Time: Full Day

        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.

        Helpful (8)
      • June 14, 2017

        5 2002 GT - ZavierL Installation Time: Shop Install Installation Cost: $100-$250


        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.

        Helpful (7)

      Questions & Answers (11 answers)

      5 Top Rated Questions

      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 (1)

      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

      Going long distance with gears I drive a 600 mile round trip for off weekends. Will this work for my car?

      • 3.73's are a great mix of acceleration while still maintaining decent gas mileage. it isn't a huge jump from the 3.55's you likely already have but will net you a better 0-60. You will be looking at roughly a 90-100rpm difference in 5th gear @ 60mph which means about 2,000rpm.

      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)

      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)
      Post Your Question
      6 More Questions
      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? 1 answer
      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
      Do I need anything else? Is anything else recommended when buying a new set of gears? Bearing kit, etc..? 2 answers

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Ring gear
      • (1) Pinion gear

      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

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