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

Market Price $319.99 You Save 20% ($64.00)
Our Price

$255.99 (kit)

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  • Item 100576
  • MPN# 100576

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Features & 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
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

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

People Who Bought This Item Also Bought

Most Helpful Reviews

5/5
Excellent product, and super fast shipping.

I received this gear in 3 days, had it put in, and it's like I'm driving a completely different car. I couldn't be happier with this product.

Helpful (3)

5/5
Great acceleration

I can definitely feel the acceleration when I step on the gas pedal. I had my local shop install the gears for about 270 not to shabby. The only thing is now my speed odometer is off which I need to adjust ...

Read More
Helpful (3)

Overall Rating 4.7 out of 5 stars
Read All 100+ Reviews

Customer Photos (15) Submit Your Photo

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You Might Also Like

21 Questions / 6 Answers

Ask a Question

What gears come stock on 2008 GT?

Anonymous

  • 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.

    KevinD92

Helpful (2)

Do you have a similar product for 3.9l v6?

Texvape44

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

    KevinD92

Helpful (1)

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

Anonymous

  • 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.

    AMJEFF

Helpful (1)

Will these help my 03 gt convertible. Looking for speed but wanting to keep the car stock ish if you know what I mean.

Anonymous

  • Larger gears will definitely aid the car in taking off faster. Though, to gain performance you can also add a cold air intake and a better flowing exhaust.

    AshleyK

Helpful (1)

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?

JeremyJAK

  • There are two differences between the Ford Performance 3.73 Gears and Install Kit (86-09 V8) and the Ford Performance 3.73 Gears and Install Kit (10-14 V8; 11-14 V6) (Item #100573) 86-09 has 75w90 gear oil where 10-14 has 75w140. 10-14 also has Ford Rear Gear Pinion Bearing - 8.8in (10-14 V8; 11-14 V6) (Item #52994) where the 86-09 kit does not.

    JeffAM

Helpful (1)

Will this gear kit fit the irs differential for an 03/04 cobra?

Luke

  • Unfortunately no it will not since the 03-04 cobra uses a different style setup. Much like all 2015 mustangs.

    WickedKobra

Helpful (1)

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Customer Reviews (100+) Write a Review

Overall Rating 4.7

out of 5 stars

Installation Time:Weekend

Installation Cost:$250-$500

  • Performance Gain 4.66 4.7
  • Fit 4.76 4.8



  • 5/5

    Installation Time: Afternoon

    May 23, 2016

    Excellent product, and super fast shipping.

    I received this gear in 3 days, had it put in, and it's like I'm driving a completely different car. I couldn't be happier with this product.

    J

    Year: 1989 Submodel: GT

    Helpful (3)

  • 5/5

    Installation Time: Afternoon

    June 02, 2014

    Great acceleration

    I can definitely feel the acceleration when I step on the gas pedal. I had my local shop install the gears for about 270 not to shabby. The only thing is now my speed odometer is off which I need to adjust but overall I recommend this product

    mikes99gt

    Year: 1999 Submodel: GT Anderson, SC, USA

    Helpful (3)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    March 25, 2014

    1998 Cobra

    Gears are a must for any mustang of any year. The stock 98 Cobra gears are 3.27's. You'll hear the debates of 4.10's minimum for the B-Headed 96-98 Cobras, but I disagree. The 3.73's provide a great acceleration, yet first gear is still usable and highway cruising won't get you past 2600rpms (and thats cruising at 80mph). This kit is a great bang for the buck, although I did use different gear oil than the Royal Purple provided because i've heard Royal Purple has gone down hill in the recent years. I also added axle bearings in my order. Couldn't be happier with the purchase.

    gkomo

    Year: 1998 Submodel: Cobra

    Helpful (3)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    March 06, 2017

    Noticeable difference

    I love everything Mustang and always dream about new things to add to my car for more speed. I don't have a lot of money and probably get to buy something once every other year. Since finances are limited I have to make sure that what I buy is not a waste of time. After lots of research I decided to go for the gears. I am very happy I did, this is the best thing I have put in my car so far. The difference was very noticeable. And for $680 (including installation) I got to say you cannot beat it. You wouldn't believe difference it makes. I am more than happy with my purchase and highly suggest a set of gears. However must say I really would like to know how it feels with the 4:10's. Maybe another time. Thanks American Muscle!

    Butch

    Year: 2006 Submodel: GT

    Helpful (2)

  • 5/5

    Installation Time: Weekend

    February 27, 2017

    What a difference!

    This rear end along with new traction clutches made this car scream! Its a beautiful thing!

    Gerggy

    Year: 1989 Submodel: GT

    Helpful (2)

  • 5/5

    August 04, 2016

    Great kit!

    I had my local Ford service department install it and they were impressed that it included everything needed for a clean installation. The new gears are much quieter than the ones they replaced. Thanks AmericanMuscle! Arizona

    BottleRocket

    Year: 2007 Submodel: GT

    Helpful (2)

  • 5/5

    Installation Time: Full Day

    May 13, 2016

    Love

    Love this set of gears, personally like the oil it comes with. Fast shipping! Thank you Am!

    Brando

    Year: 2001 Submodel: GT

    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    October 30, 2015

    3.73 gear install

    Well worth the money. Went from a 3.31 to a 3.73. Had a local speed shop install. All around pull is much better. Not realy much of a mileage loss. 80 mph is about 2600 rpm. Much more responsive. Would definately recommend this. It's a must if you only have 3.31's.

    Jsmyer

    Year: 2008 Submodel: GT Lewisburg ohio

    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    October 12, 2015

    Makes the stang way more fun to drive!

    Installed on a 03 mustang gt. Already had a tuner so adjusting the speedometer wasn't a problem. Still in the break in period but so far its a nice upgrade to the gearing of the car. No more underpowered sluggish feeling in 5th gear cruising. Can really feel the quickness off the line and through the gears. The tires can be broken loose with ease. The mechanic had mentioned that the rear needed 3 bottles of gear oil. Not sure why there are only 2 bottles included in the kit but thats no big deal. Overall If I ever own another mustang this will be the first mod to be done before any intake or engine work.

    J

    Year: 2003 Submodel: GT New Jersey

    Helpful (2)

  • 5/5

    Installation Time: Full Day

    May 07, 2014

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

    I have a 2000 GT convertible and wanted to "wake it up" For my birthday I asked my Son and Daughter for this kit. I also have a cold air intake and a 78 mm throttle body/plenum installed. I had a friend (ASE certified tech) do the install (one day). I couldn't be happier. It really woke this stang up. He also used my tuner to recal the speedometer. My friend is also a drag racer and said the kit from American Muscle was at an excellent price and had everything to do the job. Thanks A. M.

    Stang45

    Year: 2000 Submodel: GT Gahanna, OH,

    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    April 29, 2014

    Gitty up and go

    The 3.73 gears really gives the Mustang the go that it needed off the line or from a stand still. I could tell the difference that the 3.55 factory gears did for my sons car and wanted more. The 3.73 gears are very street friendly with the overdrive only running 2100-2200 rpm at 65 mph. The wife even could tell how it put her back in the seat more. I did not want the engine to scream because I have Corsa after axle exhaust and a convertible so running quite when needed was important. Great choice without going too far.

    DakotaStang

    Year: 2007 Submodel: GT Box Elder, SD, USA

    Helpful (2)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    November 16, 2013

    98 GT

    Bought the 3:73 gear set with the installation kit and had the shop install. The performance gain was very noticeable. RU you faster than REDNECK??

    ROBZGTWI

    Year: 1998 Submodel: GT CHIPPEWA FALLS WI

    Helpful (2)

  • 5/5

    April 21, 2017

    Gears

    I love new gears. Really brought car to life!!!!!!!!!!!!!!!!!!!!!!!!!

    DerekB

    Year: 1989 Submodel: GT

    Helpful (1)

  • 4/5

    Installation Time: Full Day

    February 01, 2017

    2007 GT 5 speed daily driver.

    Purchased this gear kit along with the Traction Lok friction discs for a total rear end over haul. Install is pretty straight forward with mechanical experience. Shimming the pinion and setting backlash is trial and error process that took some time. Over all I would buy again, perfect gear set for daily drivers with the 5 speed manual. Other mods include headers, intake, and tune. Coming from the factory 3.31 gears these feel much more responsive when shifting 2-4th gears.

    CodyPajamas

    Year: 2007 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    November 22, 2016

    01 cobra READ

    If you have a 99 cobra you have irs instead of a straight axel so the shop will give it to you good because it is double the headache to install. had these installed on my 01 cobra and I mean you will not be disappointed. Everyone says don't fear the gear and go 4.10's but i prefer 3.73's especially when trying to keep up on the way to cars and coffee I don't want to be running 3 grand. This gave me exactly what I was looking for, best upgrade yet.

    SvtAustin

    Year: 2001 Submodel: Cobra

    Helpful (1)

  • 5/5

    Installation Time: Weekend

    June 18, 2016

    great, cheap upgrade!

    great little kit, only thing id suggest is getting some axle bearings and seals and replacing those while youre in there, i did a trac lok rebuild as well. dont be like me and forget to shim the pinion then have to pull the bearing off and reshim! overall id suggest buying it.

    grizzdip96

    Year: 2004 Submodel: GT

    Helpful (1)

  • 4/5

    Installation Time: Full Day

    March 03, 2016

    great

    It gave my pony just what it needed to unlock it's hidden power!

    StringBean

    Year: 2002 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    March 02, 2016

    Good Price Good Product

    Works real good and I think a Good price for Ford Racing Productions comes with everything you need!

    Banshee006

    Year: 1996 Submodel: Cobra

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    November 16, 2015

    Aadded 3.73 gear

    This gear was chosen due to the reviews of others , and past experience. I have had mustangs with 4.10 and you don't give up much using a 3.73 but you have a little friendlier drive in 5th gear. Gearing on a stock GT In this year is usually a 2.73 , you can check code on door if it is listed as M under axle that is what you have, this change a lone with make a huge gain in acceleration. You will need to order a 21 tooth white speedometer gear to correct speedometer.

    mustang96

    Year: 1996 Submodel: GT va beach va

    Helpful (1)

  • 5/5

    Installation Time: Full Day

    September 28, 2015

    Not bad

    This is a nice upgrade for little more power! Not to hard to put in at all!! Took a good 7-8hrs to put it in, so worth the time and money!

    mercerjays

    Year: 2004 Submodel: GT Topeka

    Helpful (1)

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