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

71 Reviews
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  • Item #100576
  • MPN# 100576

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

Most Helpful Reviews

Nice improvement

The improvement off the line is very nice. I took it to a local shop so I can't say much about the install. But I can say when I got it back I loved the overall power out of the hole I got.

Helpful (1)

3.73 gears and install kit

Best upgrade so far came with everything needed. Dropped the car off at the shop to get the gears installed picked it up the next day and WOW!! Totally different car it seems like first, second, third, ...

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Helpful (1)

Overall Rating 4.8 out of 5 stars
Read All 71 Reviews

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7 Questions / 3 Answers

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will it fit a v6? Will this fit a 2003 v6 with a 8.8 28 spline axle?


  • Only if you have an 8.8 rear end already.


    Good Answer (1) (0)

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


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


    Good Answer (0) (0)

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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?


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Customer Reviews (71) Write a Review

Overall Rating 4.8

out of 5 stars

  • 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


    Year: 2007 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 2

    Helpful (1) (0)

  • 5/5

    Installation Time: Full Day

    May 13, 2016


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


    Year: 2001 Model: GT 'Stangs I have owned: 2

    Helpful (1) (0)

  • 4/5

    Installation Time: Full Day

    March 03, 2016


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


    Year: 2002 Model: GT

    Helpful (1) (0)

  • 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!


    Year: 1996 Model: Cobra Driving Style: Show 'Stangs I have owned: 5+

    Helpful (1) (0)

  • 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.


    Year: 1996 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 5 va beach va

    Helpful (1) (0)

  • 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.


    Year: 2008 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Lewisburg ohio

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    September 29, 2014

    Added some great get-up and go!

    Recently added these gears to my mustang and it for sure get the mustang off the line a lot quicker. My fuel mileage on the highway has not dropped off to bad as well!


    Year: 2002 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 2

    Helpful (1) (0)

  • 5/5

    Installation Time: Weekend

    April 22, 2014

    ford racing 3.73 gears are a MUST!!!

    These gears will wake up your pony and you will notice the difference From the STOCK!!! HURRY and put one in your cart today!!


    Year: 2002 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 2 Cotulla, TX 78014, USA

    Helpful (1) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    April 22, 2014

    Excellent Products

    I got my gears from and had them installed at a shop and the cars feels amazing and faster, you can feel the difference on the car already. I got everything I needed in this kit. I'm really happy with the product.


    Year: 1994 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Paramount, CA, USA

    Helpful (1) (0)

  • 4/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    March 22, 2014

    Good gains

    The product was great priced and a good upgrade, can definitely feel the gains. I would recommend this to anyone. The only negative was how much the shop charged for install. I had to pay $550 which I feel is a little high.


    Year: 1988 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 5+

    Helpful (1) (0)

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