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

9 Reviews
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  • Item #21500
  • MPN# 19588-1

  • Market Price $605.99
  • You Save 17% ($101.00)
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  • 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 2013-2014 GT500)
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 and independent rear suspensions (IRS) equipped V8 Mustangs from 1986 to 2014 and 2011 to 2014 V6 Mustangs. Requires 31 spline axles. (Will not fit the 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

Won't fit? Add an exception

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
  • Foxbody - 86, 87, 88, 89, 90, 91, 92, 93
  • Mach 1 - 03, 04
  • V6 - 11, 12, 13, 14
  • Bullitt - 01, 08, 09
  • Cobra - 94, 95, 96, 97, 98, 99, 01, 03, 04
  • GT - 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

Fits Mustangs equipped with a 8.8" rear end. Will not fit 2013-2014 GT500

Most Helpful Reviews

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 ...

Read More
Helpful (12)


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 (19)

Read All 9 Reviews
Overall Rating 5 out of 5 stars

Customer Photos (2) View All Photos

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3 Questions / 6 Answers

Ask a Question

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

tictac Year: 2012 Model: V6

  • 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.

    TimJimmy Year: 2006 Model: GT

    Good Answer (4)

Question Resolved

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

Jeramie Year: 2013 Model: V6

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

    Best Answer

    JBorelli04 Year: 2004 Model: GT Top 50 Contributor

    Good Answer (2)

Show 3 more answers Question Resolved

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?

Jona Year: 2012 Model: V6

  • 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

    65cobra Year: 2002 Model: GT

    Good Answer (0)

Question Resolved

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Customer Reviews (9) Write a Review

Overall Rating 5.0

out of 5 stars

Installation Time:Weekend

Installation Cost:$250-$500

  • Performance Gain 4.5 4.5
  • Fit 5 5
  • Bang For Your Buck 4.75 4.8

  • 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 Model: GT

    Helpful (12) (1)

  • 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 (19) (5)

  • 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 (7) (3)

  • 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 Model: GT Driving Style: Show 'Stangs I have owned: 1 MN

    Helpful (1) (0)

  • 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 Model: Other Driving Style: Street / Strip 'Stangs I have owned: 1 Fort Drum, NY, USA

    Helpful (1) (0)

  • 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 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 3 pa

    Helpful (1) (1)

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

    Helpful (0) (7)

  • 5/5

    January 23, 2008


    Great product!


    Helpful (3) (21)

  • 5/5

    March 13, 2009

    mustang lover

    i love mustnags and they love me

    chris langdel

    Helpful (7) (68)

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