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Ford Performance 3.73 Gears and Install Kit (86-09 V8)

Item 100576
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$269.99 (kit)

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      Review & Installation Video

      Product Information

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


      • Money Saving Combo Kit
      • Ford Racing 3.73 Gears - 8.8"
      • Motive 8.8" Rear End Installation and Bearing Kit
      • 1 Bottle of Ford Racing Friction Modifier
      • 2 Quarts of Royal Purple Max Gear 75w90 Gear Oil
      • Fits 1986-2009 V8 with 8.8" Solid Rear Axle


      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. This Ford Racing Ring and Pinion Gears are perfect for street, road, or race use.

      Complete Kit. This Ford Racing Gear and Installation Kit comes complete with all the components needed to swap out your ring and pinion gear. It includes Ring gear, Pinion gear, 1 bottle of Friction Modifier, 2 bottles of 75w90 Gear Oil, gaskets, seals, shims, bearings and all the required hardware.

      Legendary Ford Racing Quality. When you're adding performance parts to your Pony, you can't go wrong by installing parts from the folks that know it best. Ford Racing's legendary quality ensures years of hassle-free use.

      Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a Speedometer Gear, a Ford Racing Speedometer Recalibration Tool or a Bama SF4/X4 Power Flash Tuner is a quick and easy way to fix this issue.

      Application. This Ford Racing 3.73 Rear Gear and Installation Kit is designed for use with 8.8in solid rear axle equipped Mustangs, including the 1986-2009 GT, Bullitt, Mach 1, Shelby GT500 and 1994-1998 SVT Cobra. It will not fit the 1999-2004 IRS equipped Cobra Mustangs.

      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: 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Details

      MPN# 100576

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (100+)

      Write a Review

      Ratings Summary

      4.7 out of 5 overall rating from 100+ customers

      Installation Time: Weekend

      Installation Cost: $250-$500

      • January 31, 2020

        5 1994 Cobra - SVT9450


        Helpful (0)
      • January 19, 2020

        5 1995 GT - mattc Installation Time: Shop Install Installation Cost: $250-$500

        Love them

        I had them installed just shy of 400 bucks love the way it runs now!!

        Helpful (0)
      • January 17, 2020

        5 1994 GT - Dee0416 Installation Time: Full Day


        Love the gears...night and day difference between stock,really launches out the gate and picks up quick...100 recommend

        Helpful (0)
      • January 01, 2020

        1 2002 GT - Dingo Installation Time: Shop Install Installation Cost: $250-$500

        DONT use Ford Performance Parts

        FPP sent 3 axle bearings and no pinion bearing and race. I called AM and gave them parts number and FPP didn't recognize that number. I googled the # and it was the correct pinion bearing. They said it would take up to 8 days. My car is on the man's lift!! After 6 days, I call AM and rep. called FPP. He made it sound like they weren't sure of correct bearing. Mechanic ordered 1 from local dealer and got car off the lift. I finally receive the bearing--It was for a newer model than my car. NEVER buy FPP again.

        Helpful (1)
      • December 16, 2019

        5 2002 GT - Steve Installation Time: Shop Install

        Helpful (0)
      • October 28, 2019

        5 2002 GT - ChrisC Installation Time: Shop Install

        very pleased

        I love the way they feel, made a nice difference in the acceleration, didnt lower gas mileage that much. overall very happy.

        Helpful (1)
      • July 02, 2019

        5 1995 Cobra - MattS Installation Time: Afternoon

        Ford Racing 3.73 gear kit

        Great kit, It came with everything needed and made a big difference in the feel and drive ability of my Cobra.

        Helpful (0)
      • April 02, 2019

        5 2001 GT - Rogerdixon

        Glad I made the switch to 3.73's

        Very good gears. I love them. Contrary to what articles I have read, first gear is not useless with 3.73 gears. My mustang is supercharged, and there is no problem at all with these gears. They actually make driving in traffic much smoother as I can stay in fourth gear whereas with my 3.27's it was constantly shifting and downshifting between fourth and third. You can also maintain fifth gear at lower speeds as well.

        Helpful (10)
      • January 07, 2019

        5 2003 GT - 60years Installation Time: Shop Install Installation Cost: $500-$1000


        Excellent product I would recommend it for anybody

        Helpful (11)
      • November 18, 2018

        5 1994 GT - GTMustangTony Installation Time: Afternoon

        Great kit!

        Ford Racing gears should be your first choice for an easier installation. If you are replacing an OEM pinion, use the original shim to get the pinion depth correct the first time. Do your research if you have never rebuilt a rear. Look up Erik the Car Guy on YouTube for a good tutorial. This job is not for a novice. You will need to set your pinion preload and your backlash perfectly for a successful installation.

        Helpful (13)

      Questions & Answers (38 answers)

      5 Top Rated Questions

      What gears come stock on 2008 GT?

      • For 2008 GT's with manual transmissions will have a 3.55 whereas the stock GT's with an automatic in a 2008 Mustang will be 3.31.

      Helpful (5)

      If i get this kit for my 97 gt automatic what Speedo gear do i need to fix my speedometer?

      • The Ford Performance 3.73 Gears and Install Kit will require a new speedometer gear, however, depending on the tooth count on the drive gear, the appropriate gear may vary. If your Mustang has a 6 tooth drive gear, you will need item #383922. If your Mustang has a 7 tooth drive gear, you will need item #53685. If you Mustang has a transmission with an 8 tooth drive gear, you would technically need a 25 tooth gear, however, that was not an available option, and would would need to be made for your application.

      Helpful (5)

      What brand of bearing and seals come with this kit?

      • This gear kit comes with the Motive 8.8" rear end installation and bearing kit.

      Helpful (2)

      Hi, My 08 Roush Stage 3 comes with 3.55 gears and was curious to know what changes in performance driving I could expect by switching to the 3.73 gears? Thanks!

      • Hey Mark, So technically it doesnt have a change in power but it changes in how fast the power reaches you. Or allows you to go faster, faster. It takes power from the bottom end and moves it to the top end meaning your car will have a lower top speed but you'll feel a difference in acceleration of the car.

      Helpful (2)

      I've seen others ask about the rear wheel/axle bearings do they need to be changed out when buying this kit or does it not matter

      • The rear axle bearings would not need to be changed out when doing this kit however it would not be a bad thing to change them out so everything is new!

      Helpful (1)
      10 More Questions
      Do you have a similar product for 3.9l v6? 1 answer
      Will these help my 03 gt convertible. Looking for speed but wanting to keep the car stock ish if you know what I mean. 1 answer
      What's the difference between this kit and the one for the 10-14 mustangs? Aren't all GT differentials the same from 05-14? 1 answer
      Will this gear kit fit the irs differential for an 03/04 cobra? 1 answer
      will it fit a v6? Will this fit a 2003 v6 with a 8.8 28 spline axle? 2 answers
      If I get the gears how would I fix the speedometer to match the gear ratio 1 answer
      Wich one do you recommend more for my 95 GT convertible, 3.55 or 3.73? I will also buy cold air intake and throttle body 70mm. I use the car more in the city, but sometimes I will use on highway as well. Thanks 1 answer
      Hi I own a stock 2007 Gt convertible my top speed is around 150mph how much do you think this gear ratio will lower my top speed 0 answer
      Will this kit work for my 2001 Cobra? 1 answer
      How big of a difference is my fuel economy gonna be going with my stock 3.27 vs the 3.73? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Ring gear
      • (1) Pinion gear
      • (1) 3.8 fluid oz bottle of Friction Modifier
      • (2) one quart bottle of Royal Purple Max Gear 75w90 Gear Oil
      • Front & Rear Pinion Bearing
      • Pinion Seal
      • Carrier Bearings
      • Carrier Shims
      • Differential Bearings
      • Crush Sleeve
      • Pinion Nut
      • Cover Gasket
      • Ring Gear Bolts
      • Brush
      • Gear Marking Compound
      • Loctite

      Will It Fit My Mustang

      • Bullitt - 01, 08, 09
      • Cobra - 93, 94, 95, 96, 97, 98
      • Cobra R - 93, 95
      • GT - 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09
      • GT500 - 07, 08, 09
      • LX - 87, 88, 89, 90, 91, 92, 93
      • Mach 1 - 03, 04
      • Other - 86

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