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Eaton Limited Slip Differential - 31 Spline 8.8 in. (11-14 V6; 86-14 V8, Excluding 13-14 GT500)

Item 21500
Market Price $622.99 You Save 12% ($71.80)
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    Features, Video & Details

    • Put the Power to the Pavement
    • Assembled 8.8" Limited Slip Differential
    • Includes Carbon Fiber Clutch Packs
    • Heavy Duty
    • Requires 31 Spline Axles
    • Fits 1986-2014 V8 and 2011-2014 V6 (Excludes 1999-2004 Cobra & 2013-2014 GT500)

    Review & Installation Video

    Review & Install Video

    Limited Slip Differential. Is your stock rear end leaving you stuck in the lurch? Then you need to upgrade to a Eaton 8.8in 31 Spline Limited Slip Differential from AmericanMuscle. A Limited Slip Differential (LSD) sometimes referred to as a "Posi" will allow both rear wheels to put the power down on the pavement giving you better traction and more impressive burnouts.

    Heavy Duty. This Eaton Limited Slip Differential features a solid cast iron casing construction with a spring loaded pack and race-bred carbon fiber clutch packs. This helps the Eaton LSD deliver the highest performance even under stressful driving conditions. This LSD is virtually bullet proof and is exactly what you would expect from a name with a heritage like Eaton.

    Application. This Limited Slip Differential is the same original equipment used in the 2003-2004 SVT Cobra Mustang. It will fit both solid axle suspensions equipped V8 Mustangs from 1986 to 2014 and 2011 to 2014 V6 Mustangs. Requires 31 spline axles. (Will not fit the 1999-2004 Cobra and 2013-2014 GT500).

    Application Note. 1986-2004 V8 Mustangs came factory equipped with 28 spline axles, except for 2003-2004 SVT Cobras which were 31 spline. All 2005 and newer V8 Mustangs come equipped with 31 spline axles.

    Technical Note. You will need to reuse your factory 8.8” gear set, or upgrade to a set of our 8.8" rear gears required for this Limited Slip Differential. No aftermarket gears are included. For normal driving conditions we recommend you use 75W 90 rear gear oil. This will give you the same oil weight as factory. For colder temps or race use try 75w 140.

    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 2010 2011 2012 2013 2014 Details

    MPN# 19588-1

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Limited Slip Differential
    Installation Info
    Tech Specs
    • 8.8" Limited Slip Differential
    • Formula One race-bred carbon fiber clutch packs to limit wheel spin
    • Spring pre-load pack and cast iron case for a virtually bullet proof construction
    • Requires 31 spline axles
    • Requires 3 quarts Gear Oil
    • Requires 4 ounces of CM-19546-A1 friction modifier with initial fill
    • Fits solid or independent rear suspension
    Will it fit my Mustang?
    • Boss 302 - 12, 13
    • Bullitt - 01, 08, 09
    • Cobra - 93, 94, 95, 96, 97, 98, 99, 00, 01, 03, 04
    • Cobra R - 93, 95, 00
    • GT - 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14
    • GT500 - 07, 08, 09, 10, 11, 12
    • LX - 87, 88, 89, 90, 91, 92, 93
    • Mach 1 - 03, 04
    • Other - 86
    • V6 - 11, 12, 13, 14

    Fits Mustangs equipped with a 8.8" rear end. Will not fit 1999-2004 Cobra and 2013-2014 GT500,

      Customer Photos (7) Submit Your Photo

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        Questions & Answers (5)

        5 Top Rated Questions

        push button traction control what if any upgrades will i have to do to the "push button traction control". i want to also put 3.73 gears in. just dont want to mess anything up

        • No upgrades or modifications are required. Traction control is a system that actually operates through the rear brakes; during moments of wheel spin, the T/C system rapidly engages the rear brakes in order to slow down the wheels until traction has been regained. If you change your gears, make sure you get your car tuned.

        Helpful (5)

        I have one of these in my rear end and there seems to be about an 1/8 inch of play in and out for each axle shaft and a clunk going down the road that is definately coming from somewhere in the rotating assembly. Is this amount of play normal or might it need rebuilt/do they make a rebuild kit? I have no clue how old it is/the number of miles. The u joints/ driveshaft appear straight and in good shape.

        • The 8.8" rear should have approximately 1/8" of axle end play when properly set up. The noise may be a bearing issue, or a gear issue.

        Helpful (0)

        What gear oil does it require and any additive or anything

        • The Eaton Limited Slip Differential should run your stock weight gear oil to maintain proper lubrication of the ring and pinion gears. We do recommend a friction modifier as this is still a clutch type differential.

        Helpful (0)

        What is the difference with the 3.7 mustang differential to the limited slip differerential? I have 4.10 gears installed in my 2012 mustang 3.7, and wanted to know the difference between the stock differential for my car to this limited slip differential? Would it be beneficial to my car? If so, how?

        • If you already have limited slip no difference but if you have a standard differential. A limited slip will more regularly put power to both wheels you won't notice any difference unless you have wheelslip problems

        Helpful (0)

        Is this part required when upgrading from 2.73 factory gears to ford racing 4.10 gears? I want to upgrade my gears for faster acceleration and was just needing to know that when I purchase the gears, will I have to purchase the limited slip differential. I own a 2013 V6 Mustang with stock 2.73 gears. I want to upgrade to 4.10's. Thanks! Jeramie

        • No you don't need an upgraded differential. It would give you better grip to go with an upgraded diff., but its not required.

        Helpful (0) Show 3 more answers
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          Customer Reviews (16) Write a Review

          Overall Rating 4.9

          out of 5 stars

          Installation Time:Full Day

          Installation Cost:$500-$1000

          • Performance Gain 4.363636 4.4
          • Fit 5 5

          • 5/5

            November 18, 2018

            Great diff

            Very happy with this purchase. Had a loca shop install diff with new gears, new axle bearings, and new diff cover. Car feels much more stable. Even while tires are spinning, car goes forward in a straight line. Great purchase.


            Year: 2006 Submodel: GT

            Helpful (6)

          • 5/5

            Installation Time: Full Day

            June 18, 2018

            Eaton posi

            Works great so far. I really like it better than the mini spool it was in my car.


            Year: 1993 Submodel: LX

            Helpful (6)

          • 5/5

            Installation Time: Full Day

            April 06, 2018


            Now this is amazing. Both wheels spin and hook hard. I never knew this could help your car go faster but it does. Bog bang for your buck. This has carbon fiber clutches so its really strong


            Year: 2011 Submodel: GT

            Helpful (5)

          • 5/5

            Installation Time: Afternoon

            March 18, 2018

            Very nice

            Amazing difference in traction. My factory diff started slipping at the track. After getting it up on jack stands and testing the rear end, there is a night and day difference between the 2. The car launches much straighter and harder than it ever has. It will be nice to see the difference in my 60’ times. It was a toss up between the Easton and the Yukon. Both seemed to be a very nice part but the Eaton seemed to be the choice of most people. The Yukon seemed to have more negative reviews than the Eaton. I am pleased with this part but only time will tell on how good or bad it truly is.


            Year: 2008 Submodel: GT500

            Helpful (6)

          • 5/5

            Installation Time: Afternoon

            June 23, 2017

            Eaton LSD

            This differential made a world of difference.. it's not call Eaton for no reason cause this bad boy EATS the street like a true track monster! Better control and no one wheel wonders period.


            Year: 2004 Submodel: GT

            Helpful (7)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $1000+

            May 20, 2016

            2011 Ford Mustang

            Well not mush to say, but the Eaton Differential works very good


            Year: 2011 Submodel: V6

            Helpful (6)

          • 4/5

            Installation Time: Weekend

            September 28, 2015

            I'll give a better review when it breaks.

            I put the Eaton unit in as a replacement for a failed ford racing unit. Also put in Moser 31 spline axles, ford racing 3:83 gears, and a ford racing aluminum driveshaft, with the Steeda diff cover to finish things off. Everything went in well and I'm still in the break in. There's no unusual noises or anything else out of the norm. I'll post an update when it breaks.


            Year: 1998 Submodel: GT York

            Helpful (8)

          • 5/5

            Installation Time: Weekend

            August 22, 2014

            Eaton Differential Install

            This was a very easy install and seems to have improved the performance of my Mustang some. Acceleration is straight and true with very little tire spin unless I really get on it.


            Year: 2007 Submodel: GT MN

            Helpful (5)

          • 5/5

            Installation Time: Full Day

            July 18, 2014

            strong and reliable

            Product is strong and reliable I have had zero issues with it


            Year: 1991 Submodel: Other Fort Drum, NY, USA

            Helpful (7)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $250-$500

            June 13, 2014

            great limited slip

            this limited slip works just fine for me and my twin turbo 2011 GT at around 800hp and 800ftlbs.


            Year: 2011 Submodel: GT pa

            Helpful (8)

          • 5/5

            Installation Time: Full Day

            July 28, 2012

            good product for the price

            liked the carbon fiber dics and its seems to b more sensitive but better built than the stock carrier that came in my 06 gt


            Year: 2006 Submodel: GT

            Helpful (7)

          • 5/5

            June 10, 2010


            This unit will not work for an independent rear like the website says. However, when I realized I had purchased the wrong unit, AmericanMuscle was amazing to deal with.


            Helpful (28)

          • 5/5

            May 11, 2010

            08 gt500

            Awesome product, installed in about 4 hours with new set of 3.73 gears. Installed on 08 gt500 the c-clips are a little tricky, found it is needed to remove rubber o-ring from where the c-clip rides it is a very tight fit. No nosie great well better traction than before a must upgrade


            Year: 2008 Submodel: GT

            Helpful (17)

          • 5/5

            April 07, 2010

            Diferent Beast

            This is a great product. the quality is perfect you definitely get what you Pay for

            J Calles

            Helpful (12)

          • 5/5

            March 13, 2009

            mustang lover

            i love mustnags and they love me

            chris langdel

            Helpful (14)

          • 5/5

            January 23, 2008


            Great product!


            Helpful (6)

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