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Ford Racing 3.73 Gears (99-04 GT)

80 Reviews
Our Price


  • Item #24001G99
  • MPN# M-4209-F373N

  • Market Price $173.99
  • You Save 17% ($29.01)
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Customer Photos
  • 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
  • Mach 1 - 03, 04
  • Cobra - 99, 01, 03, 04
  • GT - 99, 00, 01, 02, 03, 04

Most Helpful Reviews


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

Helpful (2)

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 ...

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Helpful (10)

Read All 80 Reviews
Overall Rating 4.8 out of 5 stars

Customer Photos (8) View All Photos

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7 Questions / 8 Answers

Ask a Question

Do I need anything else? Is anything else recommended when buying a new set of gears? Bearing kit, etc..?


  • We highly recommend the Installation and Bearing Kit - it comes with all the bearings and shims needed for a full replacement. Also, you will need new 75w90 gear oil and to recalibrate your speedometer for the new gear ratio. I've included a link below to our complete kit that contains everything you would need. If you already have a tuner or the needed gear oil, we do offer all parts needed separately as well. If you have any additional questions, don't hesitate to give us a call - we'd be happy to help you!


    Good Answer (2) (0)

Show 1 more answer Question Resolved

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.


    Good Answer (2) (1)

Show 1 more answer Answer This Question I need this answered (0) (0)

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.


  • Definetly have a shop do it. If you don't get the shims correct you can really mess things up at worst or they'll be really noisy at best. I paid around $400 and that included parts. Money well spent.


    Good Answer (4) (0)

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Customer Reviews (80) Write a Review

Overall Rating 4.8

out of 5 stars

  • 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 (2) (0)

  • 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 Model: GT Driving Style: Daily Driver

    Helpful (10) (0)

  • 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) (0)

  • 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 (5) (1)

  • 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) (0)

  • 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 Model: GT

    Helpful (3) (0)

  • 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 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1

    Helpful (2) (0)

  • 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 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 3

    Helpful (2) (0)

  • 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 (2) (0)

  • 5/5

    February 08, 2011


    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!


    Driving Style: Daily Driver

    Helpful (4) (2)

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