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Yukon Gear Duragrip Posi Rear Differential - 31 Spline 8.8 in. (11-14 V6; 86-14 V8, Excluding 13-14 GT500)

Market Price $613.89 You Save 13% ($80.07)
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  • Item 21612

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    Features & Details

    • Put All Your Power to the Pavement
    • Assembled 8.8" Limited Slip Differential
    • Heavy Duty - Nodular Case with Forged 4320 Internals
    • Composite Clutches Included
    • Requires 31 Spline Axles
    • Fits 1986-2014 V8 and 2011-2014 V6 (Excludes 1999-2004 Cobra and 2013-2014 GT500)
    Duragrip Posi Differential. Stop doing those ridiculous one wheel burn outs by upgrading to a Yukon 8.8in 31 Spline Duragrip Posi Differential from AmericanMuscle. A Limited Slip Differential (LSD) sometimes referred to as a "Posi" will allow both rear wheels to plant the power to the pavement giving you better traction and more impressive burnouts.

    Heavy Duty. Featuring a case constructed from nodular iron, this Yukon Gear Duragrip Limited Slip Differential boast forged 4320 steel internals and composite clutches for dependable heavy duty performance and long life.

    Application. This 8.8" Yukon Gear Duragrip Posi Differential will fit solid axle suspensions equipped V8 Mustangs from 1986 to 2014 as well as 2011 to 2014 V6 Mustangs. Requires use of 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. 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# YDGF8.8-31-1

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) 8.8" Limited Slip Differential
    Installation Info
    Tech Specs


    • 8.8" Limited Slip Differential
    • Heavy Duty
    • 10 bolt cover
    • 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 the 1999-2004 Cobra and 2013-2014 GT500.

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        Questions & Answers (5)

        5 Top Rated Questions

        Which weight gear oil is recommended with this differential and should I Use synthetic or non synthetic?

        • We recommend using 75w90 rear gear oil as it is the same oil weight as the factory. If you are using this in colder temperatures, we recommend switching to 75w140. Also, synthetic oil is always better than non synthetic especially for the rear gears.

        Helpful (1)

        Im trying to keep the stock 4 lug, what gear kit and axles would work with this?

        • The Yukon Gear Duragrip Posi Rear Differential can use any Ford 8.8 gears. For axles, any 31 spline 4 lug foxbody length 8.8 axle will work.

        Helpful (0)

        if i changed to 31 spline axles could i use this for a 05 mustang with a v6

        • This Yukon Gear Duragrip Posi Rear Differential is designed for 8.8" differentials. Since your 2005 V6 is equipped with a 7.5" differential, this would not fit properly even with the correct axles. If your vehicle is equipped with an 8.8" rear, then this would work well with 31 splined axles.

        Helpful (0)

        Would this be able to fit in a 99-04 V6?

        • This differential will not fit a 99-04 V6 Mustang, as they are equipped with 7.5" differentials. To utilize this differential it would require an 8.8" differential and the associated components such as the carrier, axles, etc.

        Helpful (0)

        Is a Friction modifier needed? I know the OEM differentials require a friction modifier, does the Yukon need the same added to it?

        • Not if you use Royal Purple. If you use Mobile 1 or anything else, yes.

        Helpful (0) Show 2 more answers
        Post Your Question

          Customer Reviews (11) Write a Review

          Overall Rating 3.5

          out of 5 stars

          Installation Time:Full Day

          Installation Cost:$100-$250

          • Performance Gain 3.222222 3.2
          • Fit 3.9 3.9

          • 1/5

            Installation Time: Full Day

            February 16, 2019

            Why are you guys still selling these

            Absolute garbage whines when I turn I used non synthetic gear oil and added the friction modifier just like Yukon specified but it still is very loud I installed it myself checked the backlash and shimmed it correctly and checked the gear pattern with the paint everything was perfect until after the break in period it started making lots of noise and it doesn’t slip well on turns I’ve seen one of these in person blowing up on a stock 4.6 4v that was after I bought mine I’m planning on upgrading very soon bottom line why would you upgrade your stock differential to this when these tend to break easier


            Year: 2004 Submodel: Mach 1

            Helpful (0)

          • 1/5

            April 06, 2018


            Dont get this it will break, ended up returning it and theow in 10-15 more bucks to get eatons lsd diff. It has carbon fiber clutches and makes both wheels hook HARD


            Year: 2011 Submodel: GT

            Helpful (4)

          • 1/5

            Installation Time: Afternoon

            February 27, 2018


            I only have 400hp and on the 5th run it went done no more 100 JUNK!!!!


            Year: 2002 Submodel: GT

            Helpful (3)

          • 5/5

            February 19, 2017

            Use non synthetic.

            AM said to use a synthetic oil but if you go on yukons web site they clearly say to use gear oil non synthetic which is what I used and it's whisper quiet and no issues yet the duragrip posi works flawlessly.


            Year: 2014 Submodel: GT

            Helpful (6)

          • 1/5

            Installation Time: Afternoon

            November 14, 2016


            Got around 670 street miles and 2 trips to the track before this thing exploded. Took a bunch of pics and sent to Yukon, their support was awful. They may make great stuff for trucks but I'll never use a Yukon again. 670rwhp ProCharged E85 '13 - in just a couple months I'm buying a new diff, gear set, bearings, and paying shop labor to do this again, do yourself a favor and find another product.


            Year: 2013 Submodel: GT

            Helpful (4)

          • 5/5

            October 04, 2016


            Very quality product..and fast and great shipping from American muscle


            Year: 2012 Submodel: V6

            Helpful (5)

          • 4/5

            Installation Time: Full Day

            September 24, 2015

            nice upgrade

            Everything went in good except for the clips its a pretty tight fit other than that awesome upgrade


            Year: 2008 Submodel: GT colorado

            Helpful (4)

          • 5/5

            Installation Time: Afternoon

            January 16, 2015

            power posi

            This product offers power traction in various conditions that improved my wheel spin. Even ender normal driving conditions. I'm pleased that this is what you need. With out over thinking performance as a daily driver it has the ability.


            Year: 2000 Submodel: GT Hollywood, FL, USA

            Helpful (5)

          • 5/5

            Installation Time: Shop Install

            Installation Cost: $100-$250

            September 20, 2013

            awesome product and awesome price!!!

            I broke the spider gears in my 2012 GT differential. I debated over the Yukon vs. the Eaton, but after talking with many dealers, I found that they are pretty much built with the same design. After the install, it seems to be working great with no noise or problems. I would highly recommend this product based on the fact that its an upgrade over ford traction lok without a large price difference.


            Year: 2012 Submodel: GT Sumter, SC, USA

            Helpful (4)

          • 5/5

            Installation Time: Weekend

            May 01, 2013

            Great Product For The Price!

            i had blown my original LSD while having fun, installed this with some issue due to me but once that went away and i broke it in, phenomenal product. installed and had a solid feel of the rear end and grip!! Not to aggressive for street but aggressive enough to hold it's own!


            Year: 1989 Submodel: GT NH

            Helpful (4)

          • 5/5

            Installation Time: Afternoon

            December 22, 2012

            This product has espectacular

            The car improve at the start. And the quarter mile time improve also.


            Year: 2000 Submodel: GT

            Helpful (8)

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