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Ford Performance 3.55 Gears and Install Kit (86-09 V8)

Item 100575
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      Review & Installation Video

      If you're looking for a little bit more acceleration and performance off the line but without compromising your fuel economy, a set of 3.55s from Ford Performance might just be the solution. Now, this kit will fit the 8.8 solid rear axle in your Mustang and will not only include the brand new ring and pinion as you can see but also everything you need to get them set up and in place. Your price point for this kit will land you right in the mid $200 price range and the install, listen, it's not gonna be for everyone out there, it will require some specialty tools so therefore we're gonna knock this one up to a three out of three wrenches on the difficulty meter with a little bit more detail to come later in the video. So it's no big secret that factory gear ratios on most of these earlier cars, including the fox body, the SN95 but even some of the early S197s weren't exactly ideal for scorching off the line acceleration, in fact, it was quite the opposite. Now most of these earlier cars came with a 2.73, a 3.08 gear or in some cases a 3.27. But that was pretty much it until the S197 ushered in an optional 3.55. But with all that said a lot of guys might not want to make a massive jump to a 4.10 or higher gear ratio maybe for fuel economy reasons or maybe they just don't see the need for it with their particular application and therefore would like to compromise with a middle of the road gear ratio, and in that case I think the 3.55 is a perfect option. And on top of that power adder cars out there might want something to get the car moving a little bit more but don't wanna go with a numerically higher gear ratio as you want the car to stay in boost a little bit longer and not be shifting consistently. So there are many reasons why a gear change is important in your use, and your application is no doubt the biggie. As far as the physical gears and construction is concerned here with this kit, well, nothing but the best from Ford Performance as you might expect, including the strong forge construction, the CNC cut, along with the [inaudible 00:02:05] teeth and then finally the black oxide coating. Everything has been made here in the USA and Ford Performance claims they're gonna be the quietest gears available on the market for your 8.8 rear. Now that last claim in regards to noise should be taken with a grain of salt because a lot of times with a gear install any noise you might receive in the rear end might not always be coming from the gears themselves but rather the installation or the setup which does lead us to the next part of this product and that is the installation kit. Now this is also from Ford Performance and does include everything you need to get that brand new ring and pinion set up in your 8.8, including brand new bearings, new seals, new shims, crushed leaves, pinion nut, some gear marking compound and brush to check your pattern and depth of course, brand new diff cover gasket and even two quarts of the 75 90 gear oil in addition to the required four ounces or 3.8 ounces of your friction modifier. So to put it shortly here guys, a very complete kit and one that will be very beneficial to either you or your mechanic when it comes time to get everything installed. Speaking of the installation, listen guys, gear installs are a bit of an art form and do involve a decent amount of work including some use of some specialty tools. So because of this, we're gonna knock this one up to a three out of three wrenches on the difficulty meter here and maybe a day to a half a day in the garage depending on your expertise and how fast you like to work. Now if you've never done something like this before and you're a little apprehensive to tackle this installation you might wanna shop around to some of your local shops and see what they'll quote you for the install. My guess is it's gonna be somewhere in the ballpark of 500 bucks, give or take. On the other hand, if you've done a few gears installs in your day and this is just another day in the garage for you, you already know what to expect and you're definitely going to save yourself some money on some labor. Another thing to keep in mind here with a gear swap like this is that depending on how drastic you go, your speedometer will more than likely be off considerably and at that point, you should correct it. Now '79 to '98 V8 owners out there can simply swap out that speedo gear and that will be the easiest and most cost-effective way to do this. '99 and newer owners, on the other hand, you can either go about changing this through a handheld tuner or a custom calibration, or you can even grab the Ford Performance speedo recalibration device or box here on the site which is gonna run you about a couple hundred bucks. But wrapping this one up guys, if you're suffering from an extremely tall gear in your V8 powered Mustang and wanna fix that without going crazy, a set of 3.55s from Ford Performance would be a great compromise and you could grab your set right here at

      Product Information

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


      • Money Saving Combo Kit
      • Ford Racing 3.55 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 3.55 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# 100575

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (26)

      Write a Review

      Ratings Summary

      4.7 out of 5 overall rating from 26 customers

      Installation Time: Weekend

      Installation Cost: $250-$500

      • November 15, 2019

        5 2004 Mach 1 - Chingon650 Installation Time: Shop Install


        Awesome works great and easy to install. I had a friend install it on his shop.

        Helpful (1)
      • January 17, 2019

        5 1989 LX - JeffreyH Installation Time: Shop Install

        Great product

        Thanks fast shipping items as described thanks !!!!!!!!!!!!!!!!!!!!!!!!

        Helpful (3)
      • August 24, 2018

        5 2000 GT - JamieM Installation Time: Afternoon

        Just what I needed

        This was everything that I expected from a Ford Performance product, at a reasonable price. The gear change was a must going from naturally aspirated to supercharged. I previously had 4.10 gears and I'm happy with the outcome of the 3.55 gear selection. It gave me a great balance of power and highway cruising.

        Helpful (10)
      • July 31, 2018

        5 1990 LX - LouisN Installation Time: Afternoon

        new gears

        nice clean new gears work very well and speeding delivery

        Helpful (8)
      • February 20, 2018

        5 1998 GT - PabloR Installation Time: Weekend

        Needed upgrade

        The difference in acceleration is noticed, but you don’t sacrifice highway drivability!

        Helpful (13)
      • November 18, 2017

        5 2007 GT - BJM Installation Time: Shop Install Installation Cost: $250-$500

        Everything needed

        I purchased a high mileage 07 GT that definitely needed the rear ending rebuilt. This kit has all the parts to make it work like it did from the factory.

        Helpful (11)
      • October 16, 2017

        5 1993 LX - LewieA

        Great gears

        Great gears for 93 with AOD transmission. Item shipped quick

        Helpful (10)
      • October 02, 2017

        5 2004 V6 - Clay Installation Time: Full Day

        Good kit

        All quality parts. Installation was simple. Removal of old was a pain... Set-up and alignment with new diff was time consuming but not hard. Installed in a crown vic police and ended up needing a little more oil than the 2qts provided. Overall great kit, would recommend to anyone.

        Helpful (10)
      • September 16, 2017

        5 1998 GT - Gabe Installation Time: Shop Install Installation Cost: $250-$500


        Nice upgrade. Takes off a lot quicker and helps overall acceleration.

        Helpful (10)
      • July 24, 2017

        4 2002 GT - Mikeee1328 Installation Time: Shop Install Installation Cost: $250-$500

        It's a great kit!

        This is the best deal you'll find on gear kit! The only downside is you only get 2 quarts and it takes more than that. Other than that it's great!!

        Helpful (13)

      Questions & Answers (16 answers)

      5 Top Rated Questions

      If the 8.8 requires 3 quarts of gear oil why are there only 2 quarts included in the "complete" kit?

      • The fluid capacity of the 8.8 rear for 1986-09 Mustangs is 2qts of gear oil or approximately 3.8 pints.

      Helpful (5)

      What other bearings are needed to rebuild my diff that arnt included in this kit

      • The Ford Performance 3.55 Gears and Install Kit will include front and rear pinion bearings, carrier bearings, differential bearings. In addition to this, axle bearings would be required to completely rebuild your rear end.

      Helpful (2)

      Would this be a good gear ratio for a person who uses his car as main mode of transportation?

      • Yes, 3.55 is a good performance option for a daily driven Mustang.

      Helpful (1)

      If I install these in my 95 Mustang Gt. Will I also need to get a Ford Speedo Gear to keep speedo right? I be using these to replace a set of 3.09 stock gears..

      • When installing the Ford Performance 3.55 Gears and Install Kit you will need to install a speedo gear to correct your speedometer reading. You will require either a 23T speedometer gear paired with your stock 8 tooth drive gear, or a 7 tooth drive gear paired with a 20T speedo gear. We typically recommend against 23t speedo gears, as they have a tendency to wear rapidly.

      Helpful (1)

      Have a 2006 GT Automatic is this too high of a gear to install?

      • This gear ratio would not be too high no! If you drive some back roads and highway this would be a very good ratio to go with.

      Helpful (1)
      Post Your Question
      10 More Questions
      Hey I have a 06 gt, how much of a difference should i expect putting 3.55 gears in. 1 answer
      Aside from the speedo gear upgrade, is there any tuning that needs to be done or is all plug and play? 1 answer
      hi whats the difference in fuel mileage between 3.55 and 3.73 1 answer
      Can I run either 28 or 31 spline axles with these? 1 answer
      Own a 2007 Mustang GT changing the rear differential seal do you have to torque the bolts down. 1 answer
      Will this kit work with the 03-04 Cobra IRS, and if not which one can be used? 1 answer
      I have 1996 Mustang GT, and wonder after the Gears replace, do I need to use tuner to reprogram it? 1 answer
      What if my Mustang already has 3.55 gears stock...will this kit be better then stock in anyway? If so how? 1 answer
      What Speedo gear would i need for my 97 gt after installing these gears to calibrate it properly 1 answer
      If I get this kit for my 97gt what Speedo gear do I need to get to correct speedometer? 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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