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

Market Price $319.99 You Save 16% ($50.00)
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$269.99 (kit)

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  • Item 100576

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    Features, Video & Details

    • 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

    Review & Installation Video

    Review & Install Video

    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

    CA Residents: Warning: California's Proposition 65

    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
    Installation Info
    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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    Questions & Answers (27)

    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 (4)

    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 (3)

    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)

    Do you have a similar product for 3.9l v6?

    • We do not have a gear and install kit for the 3.9L V6 motor.

    Helpful (1)
    Post Your Question
    10 More Questions
    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
    I just bought a '96GT and would like to wake it up a bit. I know that changing the gearing will help off the line, but what about at cruising speeds? This mod will change cruising RPM, trying to get an idea of how much? 1 answer
    Own a 98 gt and I was going to buy this with the traction rebuild kit and the Yukon duragrip differential. Do you recommend anything else that I might need for a swap out? 1 answer
    What speedo would I need for the 3.73 gear on an 88 gt? 1 answer
    I have a 01 Bullitt and was considering doing the swap. What will need to be done for correct speedo calibration? 1 answer
    i have a 97 cobra question is what is the spline count on the rear end and will this gear set up work, i was talking with the shop i plan on having them install and they said something about making sure the spline count was the same as whats on the car now, and what speedogear will i need to add to it to make it read right. 1 answer
    It fit to mustang gt 2004 1 answer

    People Who Bought This Item Also Bought

    Customer Reviews (100+) Write a Review

    Overall Rating 4.7

    out of 5 stars

    Installation Time:Weekend

    Installation Cost:$250-$500

    • Performance Gain 4.610169 4.6
    • Fit 4.779661 4.8



    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      September 10, 2018

      Great package

      Got these gears and install kit along with axle bearings and gaskets. Had them put in by someone. Happy overall with performance and quality. AM sent package promptly and well packaged. So much difference from factory gears.

      DwaineW

      Year: 2004 Submodel: GT

      Helpful (0)

    • 5/5

      Installation Time: Full Day

      September 04, 2018

      Outstanding Kit

      I had to replace my rear end pinion seal and took the chance to change out the gears, so I bought this set. I had a mechanic do the work at 85/hr for 5.5 hours of work. He said the kit was great and had everything he needed to do the job right. I have had no problem with gear whine, since the mechanic did the job right and even pulled the carrier twice to ensure he had the backlash set correctly. As far as performance goes, the car is quick… much quicker. The gears definitely get you into the power band much quicker and will put a smile on your face. MPG wise not really much of a change from my stock 3.31s when driving normally, but who really does that right? Maybe dropped 2-3MPG, but again this kit will put a smile on your face. I would recommend picking up the Ford Racing rear axle bearing and seal kit along with a rear differential cover, since you will have everything pulled apart at this time. I also picked up the Ford Racing differential cover, which looks great and will make it very easy to drain and fill the rear axle in the future. Would highly recommend this item.

      JellyRollPA

      Year: 2008 Submodel: GT

      Helpful (0)

    • 4/5

      Installation Time: Afternoon

      September 01, 2018

      06 GT gear swap and rebuild

      Quick review on my 3.73 gear swap Picked up my 06 GT after installing the Ford Performance 3.73 gear kit and Trac Lok rebuild. Total labor costs was $495. At 168k, mechanic said I really needed the diff rebuild. Car runs fantastic. A little faster off the line and then takes off about 1 second in, when it hits the power band. Acceleration is amazing in 3rd and 4th. Not sure on gas mileage yet but probably not great. I don't regret not using the 4.10s because of my highway miles but if you are wanting whiplash off the line, 3.73s probably will disappoint. For me, 3.73s are perfect. Next I need a tuner and CAI. Also, without a tuner, my car is running 75 MPH at 87 on the speedometer. Mechanics note: don't use the royal purple oil that comes with the kit. It's garbage. Also, my mechanic said you need 4 heat cycles on the gears as a proper break in period. Don't worry about miles, it's the heating and cooling of the clutches and gears that allows the oil to bond properly

      CaseyG

      Year: 2006 Submodel: GT

      Helpful (0)

    • 2/5

      Installation Time: Shop Install

      Installation Cost: $500-$1000

      August 22, 2018

      Not sure about this

      We needed to replace the diff bearings. Had a mechanic do the install and he says it had everything he needed and went together well. It makes a lot of noise and vibrates very bad. The mechanic said that now it needs a new driveshaft. I have one coming in tomorrow and will let him install that to see if it clears up. Not sure at this time.

      JeffW

      Year: 2007 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Full Day

      August 21, 2018

      3:73 kit

      What a difference these gears make , it woke up the car totally different feeling and it’s more fun to drive

      MohamadR

      Year: 1994 Submodel: GT

      Helpful (0)

    • 5/5

      June 01, 2018

      Great price

      Great price for the quality and fast shipping !!!!

      DenisJr70

      Year: 2002 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      May 06, 2018

      Love these gears

      The kit comes with everything you need my mechanic had no problem installing them

      AlfredoZ

      Year: 2000 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      April 30, 2018

      Great

      Fast and easy install,great valve for your money really feel the difference

      EdwardoA

      Year: 1984 Submodel: Other

      Helpful (2)

    • 5/5

      Installation Time: Full Day

      April 26, 2018

      Awesome package!

      Made for a great first time DIY installer like myself. The kit is nice because it comes with 2 crush sleeves and 2 pinion nuts in total which came in handy after I over torqued the crush sleeve my first attempt. Gears improved performance as well as no sound coming from rear end. Happy customer!!

      DrewE

      Year: 1999 Submodel: GT

      Helpful (2)

    • 5/5

      April 25, 2018

      Great product

      Everything you need to install the ring and pinion. No guess work involved.

      jasonm

      Year: 1993 Submodel: Cobra

      Helpful (3)

    • 5/5

      April 24, 2018

      Everything You Need

      Item arrived with all the pieces as shown. Was my first time regearing a car on my own (have replaced rear ends never regeared). The pieces all fit together very well and have been in the car for a year now and zero issues. Highly suggest having experienced help though as it took me awhile due to lack of tools to properly complete the job.

      LeviA

      Year: 1995 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Full Day

      April 19, 2018

      All you need for the gear swap

      Just got this gear installed yesterday. The kid had everything I needed. Will take time to break in the gears. But so far so good.

      DmitryS

      Year: 1997 Submodel: Cobra

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      March 09, 2018

      Can’t grab that $100 bill

      Man what a difference throw you back in the seat. Place a a $100 bill on the dash when I hit second gear I bet you can’t grab it. If you do it yours!!!

      LonnieT

      Year: 1993 Submodel: Cobra

      Helpful (5)

    • 5/5

      Installation Time: Full Day

      March 06, 2018

      3.73 gears!!

      My 07 auto has some engine upgrades but the 3.31s in the rear were not keeping up with the power. After these were installed the car just simply came together for an ultimate daily driver. No whining issues(so far). Off the line or stand still car just wants to take off. If you are on the fence with 4.10s and 3.73s go 3.73 first but I think the 4.10s for daily driving would be a little much. After the 93p tune came in speedo was fixed and CANT wait to try the race tune soon!!

      Dmadlock123

      Year: 2007 Submodel: GT

      Helpful (5)

    • 4/5

      Installation Time: Shop Install

      February 26, 2018

      Good set

      Great bang for your buck well Worth the price was packaged well also got here within two days

      WillyC

      Year: 2000 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      February 01, 2018

      Gears for everyone

      Good gear ratio for a daily driver. Also didn’t affect the gas mileage much. I should of done this a long time ago. Would recommend this for everyone

      KevinA

      Year: 1996 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      January 20, 2018

      3:73 gears

      should of went with lower gears maybe 4:11 but they worked fine

      Bob

      Year: 2006 Submodel: GT

      Helpful (3)

    • 4/5

      Installation Time: Afternoon

      January 06, 2018

      Gears

      Great product great price easy install. Recommend everyone to use American Muscle.

      korys

      Year: 1990 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      November 27, 2017

      373 gear

      Excellent product, fast shipping, awesome customer service...

      Allen

      Year: 2003 Submodel: GT

      Helpful (3)

    • 1/5

      Installation Time: Shop Install

      Installation Cost: $1000+

      November 20, 2017

      No stars!!!!

      Tried to get one over on me! Send me used gears!!!! Car still apart waiting for A.M. to make it right! Very unsatisfied!! Go figure they wont let me give no star!!

      GregL

      Year: 1992 Submodel: LX

      Helpful (13)

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