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Ford Performance Traction - LOK Limited Slip Differential w/ Carbon Discs - 31 Spline 8.8 in. (11-14 V6; 86-14 V8, Excluding 13-14 GT500)

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  • Item 24062
  • MPN# M-4204-F318C

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    Features, Video & Details

    • Put the Power to the Pavement
    • Assembled 8.8" Limited Slip Differential
    • Includes Carbon Discs
    • Heavy Duty
    • Requires 31 Spline Axles
    • Fits 1986-2014 V8 and 2011-2014 V6

    Review & Installation Video

    Review & Install Video

    Hey guys, Stephanie with here with this Ford Racing LSD for 31 spline 8.8 rears, or to break it down, 86 to 14 V8s and 2011 to 2014 V6 Mustangs. This Posi unit from Ford Racing is going to be a good option for the guys out there with an 8.8 rear that are looking to replace their diff with the next upgrade over stock. This diff has carbon discs and requires the use of 31 spline axles, which gives it that upgrade over the factory components. And if you're planning on or already have some bigger power and torque numbers from your 'stang, or the car sees some track time or hard launches, a differential upgrade should be something that you're looking into. There are a couple of reasons to change or upgrade your differential. Maybe you've got a stock diff and it's just getting old or chattering, or maybe you plan on hitting the drag strip and you've got some power that you'd like to cleanly get to the ground. Either way, this Ford Racing diff would be a good option, because it's got a balance of being an upgraded part that can handle more power and torque, but that isn't such an upgrade that it wouldn't make sense for a completely stock car to upgrade to. This diff is actually the same diff that came from the factory in the O3 to O4 Cobras, so it's a beefed up version of a factory style diff if you have any other Mustang besides the O3 to O4 Cobra. Like I mentioned earlier, this diff is going to require the use of 31 spline axles, so if you've got an O4 and under V8, you're looking at upgrading your axles, since those cars came from the factory with 28 spline axles. If you've got an O5 and up you can reuse your factory axles with this diff, but you're still looking at an upgrade due to the fact that this diff has carbon discs. The carbon fiber discs that I keep referencing refers to the clutch pack. This diff uses the same carbon fiber clutch pack that's used in the Cobra and Shelby SVTs, and the carbon friction plates are much more durable and they're designed for a higher torque than the stock friction plates are. If we take a step back for a minute, the point of a limited slip differential, or an LSD like this one here, is to allow both rear wheels to put power to the ground and give better traction to both rear wheels. So the thought is, if there's any type of open diff transfer or uneven transfer of power and torque to one particular wheel over the other, that'll create a useless wheel spin where the car loses its forward momentum, the LSD is designed to eliminate that spin. It'll transfer the torque of both wheels evenly and will have a few benefits in both street and track applications. This means a stable differential lock pattern that won't fail due to the upgraded components, and no slipping, more durability, gentle transitions, and even a quiet operation. This is going to work for cars with both solid axle and IRS, or independent rear suspension, and you'll need to reuse yours or grab a new 8.8 rear set since this diff will not come with aftermarket rear gears. One other note would be the recommended use of 75W90 rear gear oil, since those will give you the same oil weight as the factory, and you're going to need three quarts of that and four ounces of friction modifier for the initial fill. When it comes to the price, this rear diff is going to cost $230, and it's going to be the most wallet friendly option on the site when it comes to LSDs. There are some beefier options on the site if you really need to upgrade for power reasons, but those are obviously more expensive, and it's nice to see an upgrade over the factory components from Ford Racing that you aren't going to have to turn the red light on for. As for the install, you're going to need some experience for this one. You'll need a few different wrenches and sockets, but an impact gun is going to help you speed things up here, even though you can do this install with all manual tools if you wish. A lift would also really help, and you're going to need a torque wrench to do this properly. You're looking at about four hours' time and a three out of three wrenches on the difficulty meter. You're going to need to get to the diff itself, so this means pulling the rear wheels, dropping the rear brake assemblies, draining and removing the rear diff covers, so you will need something to drain into. Once you have the diff uncovered, this is where the benefit of mechanical knowledge will come in. You'll need to rotate the axles until the diff pin retaining bolt is accessible, because you'll need to get this pin out so you can push the rear axles out of the diff. Once those are out, you're looking at backing out the diff-bearing cat bolts and pulling the diff out of the car. You need to reinstall the shims that are on each side of the diff bearings the exact same way that they came out, so keep track of those. The new diff bearings will need to be pressed onto each side of the new diff and you can reuse the ring gear off of the old diff. And after that, it's just a matter of reinstalling things. Reinstall the shims, reinstall the diff and the retaining pin, the axles, and the housing cover as well. Now, this is obviously a quick overview of the install, but I wanted to give you guys an idea of what it would take so you can make a decision as to whether or not you're going to install this yourself, or you're going to take it to a shop. Wrapping things up here, the Ford Racing LSD with carbon discs is to be used in 8.8 rears and with 31 spline axles. It's an upgrade over the factory diff unless you have an O3 to O4 Cobra, and in that case, it's an exact replacement. This diff is a good option for those looking for a maintenance replacement, or those looking for something to make sure that they get some extra torque planted squarely to the ground. And you can check it out some more right here at

    Limited Slip Differential. Is your stock rear end leaving you in the lurch? Then you need to upgrade to a Ford Racing 8.8" 31 Spline Traction-LOK Limited Slip Differential with Carbon Discs 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.

    Carbon Discs. This Ford Racing Limited Slip Differential uses the same carbon fiber clutch pack used in the Cobra and Shelby SVT Mustangs. Carbon-fiber friction plates are much more durable and are designed for higher torque over there stock counterparts.

    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. 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

    What's in the Box
    • (1) Limited Slip Differential
    Installation Info
    Tech Specs
    • 8.8" Limited Slip Differential
    • Includes Carbon fiber clutch plates for increased durability
    • Will accept anti-lock exciter ring
    • 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

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    41 Questions / 11 Answers

    Ask a Question

    What do i need to change on my 1998 V6 to make this work?


    • The 98 v6 will have stock a 7.5 inch rear end. You will need an 8.8 inch rear end housing, 31 spline axles for said 8.8 housing and 8.8 inch gears along with bearings, oil seals and such.


    Show 3 more answers Helpful (2)

    I have a 2007 GT and I'm planning to uprgrade the hearing to 3.73s, I also want to put this Ford performance traction Posi LOK in will I still need the LOK rebuild kit if I purchase this Ford performance traction LOK?


    • No, you would not need to purchase the LOK Rebuild Kit if you purchase the Ford Performance Traction - LOK Limited Slip Differential w/ Carbon Discs.


    Helpful (1)

    Will adding this to a 2012 V6 Mustang help at all in the 0-60 and 1/4 mile?


    • Pending on driving experience and track/road conditions...Maybe...but marginal gains as the only Mod and it shouldn't be the first Mod. It's price is the biggest selling point for this particular unit if 1/10th per 1/4 mile run means that much to you.


    Show 2 more answers Helpful (1)

    The term LOK, is it an abbreviation of the word LOCKER, such as Detroit Locker? If so, it would be a scary thought/experience in a street driven vehicle. The rear Wheels of my 2014, six cylinder, Mustang equipped with a limited slip differential has 38 deg. to 42 deg. play / free rotation before coming up against the resistance of the power train. Am Looking at poor pinion to ring gear set up, or severe internal wear? I need a straight answer, so if you would be so kind, I would appreciate your insight.


    • The Ford Performance Traction - LOK Limited Slip Differential is Ford's clutch type limited slip, and is not a locker. Ford does not measure rear end play based on a measurement at the wheel, but rather at the driveshaft, or at the pinion gear (with the diff cover removed) If you feel their is excessive play in the rear end, this could indicate wear, however if rear gears were recently installed a poor setup could also show the same symptoms.

      Rob D

    Helpful (0)

    Does this use a 7/8" or 3/4" crosspin?


    • The Ford Performance Traction - LOK Limited Slip Differential will utilize a 7/8" cross pin.

      Rob D

    Helpful (0)

    I wanna upgrade to 3.73 gears and since the stock LSD has to come out I wanna replace it with the Ford performance LSD. Can I still use my stock axles with the new LSD?


    • This Ford Performance Traction - LOK Limited Slip Differential, Requires the use of 31 spline axles. As long as the axles you currently have are 31 spline it will fit perfectly.


    Helpful (0)

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    Customer Reviews (59) Write a Review

    Overall Rating 4.8

    out of 5 stars

    Installation Time:Full Day

    Installation Cost:$250-$500

    • Performance Gain 4.681818 4.7
    • Fit 4.977273 5.0

    • 5/5

      August 31, 2009

      The way to go

      Mix these up with 31 spine axles and not only will it future proof your ride but i makes burn outs and sliding much more predictable at the limit and if you have 4.10s this is how you find your traction


      Helpful (21)

    • 5/5

      October 14, 2010


      The clutches in my old posi were worn so I decided to upgrade to 31 spline axles, which I also purchased with the FMS posi. As expected, no fitment issues. So far 16 passes on the 1/4 mile, hard launches with drag radials and a fair bit of street use and all is well. Very satisfied with the product.

      Barry Stanley

      Helpful (11)

    • 5/5

      October 14, 2010

      Great Diff

      I paired this diff with Moser axles and its seen plenty of burn outs and hard launches on drag slicks. I cut 1.6 60ft times with a bolt on 04 Mach 1. Great diff for the price and great traction.


      Year: 2004

      Helpful (9)

    • 5/5

      Installation Time: Afternoon

      June 10, 2014

      Cheap for a carrier

      Pretty cheap for a carrier, new clutches, new spiders, S spring, and center pin. They even give you the bolt that locks the pin in. If you priced it seperatly its definatly worth it. Since its a cobra carrier it does not have notches where the clutch packs lock in. This is where my old carrier cracked and failed. Fits all 8.8 31 spline, including Bronco's/F-150's like mine.


      Year: 1995 Submodel: Other Piscataway Township, NJ, USA

      Helpful (8)

    • 5/5

      December 11, 2010

      Great improvement!

      Bought this as part of a complete rear-end rebuild on a 1995 GT. My old posi was doing 1 wheel burn outs and this fixed that issue. You can feel it pull a lot harder now. This unit was very well built too- much higher quality than the stock one.


      Year: 1995 Submodel: GT

      Helpful (8)

    • 5/5

      October 14, 2010

      great differential

      installed this differential into my 2001 mustang Bullitt. this is a great up grade from the stock differential. both wheels lock together when you throw the torque to it. would recomment this differential to anyone that wants to up grade from the stock unit. all in all I love the way this diffenential works.


      Year: 2001

      Helpful (8)

    • 5/5

      October 14, 2010


      This did exactly what it said it would. It's a great upgrade and no more complicated to install than any other diff. I was in the back changing out the gears so I decided to do the T-Lok as well. Thinking about getting steeper gears? Might as well do the T-Lok at the same time and save time, money, and knuckles!

      Dave B.

      Helpful (8)

    • 5/5

      May 11, 2010

      great difference!

      this diff couples with some 3.73 gears you can really feel it putting more power to the ground more than your stock diff. cant wait to strap some slicks on and whoop on on some people on the street!


      Helpful (7)

    • 4/5

      Installation Time: Afternoon

      January 27, 2012

      best bang for your buck with tloks

      i have one of these in my 95 5.0 which has 4.11 in it and launching it is much easier now. this isnt that hard to put in yourself in a couple hours and it beats paying over 400 for the other tloks out there. i also have one in my truck the extra traction realy helps out in the mudd and snow.


      Year: 1995 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Afternoon

      May 17, 2015

      Traction Lock Carrier

      The carrier was well packaged and delivery was fast. Fit was perfect. Run out was less than 0.001". Very pleased. Replaced my existing carrier which had a bad run out 0.008".


      Year: 2007 Submodel: GT500 SEPA

      Helpful (5)

    • 5/5

      Installation Time: Afternoon

      October 13, 2013

      Love this diff.

      Great difference in the feeling that's it is not going to break when I launch at the track.


      Year: 2007 Submodel: GT Houston, TX

      Helpful (5)

    • 5/5

      Installation Time: Afternoon

      October 13, 2011

      Great Upgrade!!

      My stock diff was going bad so I took advantage of upgrading it to this with 31 spline axles and an aluminum driveshaft. I recommend a reputable shop to install it if you want it done right. Great upgrade and love that it comes with the carbon discs.


      Year: 2003 Submodel: GT Wayne, PA

      Helpful (5)

    • 3/5

      October 14, 2010

      thank you for your excellent serveces

      I like this item but when i went to the race my diff slide a litle bit however when i was on the street that is good just whit my drag weel my right weel spin and my left weel stay wihtout spine and its very essy to instal that whit good tool

      Pierre-Luc Poitras

      Helpful (5)

    • 5/5

      Installation Time: Weekend

      February 08, 2016




      Year: Pre-79 Submodel: Other FT WORTH TX

      Helpful (4)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      May 14, 2014

      Great Price

      First time we used you guys. Great price,was here in one day. Great experience. Thanks Pine Grove Auto Sales and Service


      Year: 2007 Submodel: GT Pine Grove, PA 17963, USA

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      December 12, 2013

      Ford Racing 31 Spline Cobra Differential

      I drag race my street licensed 2002 mustang GT, and it's just a matter of time until you snap the factory 28 spline axles, and have to have your car towed home, if you use any kind of street/strip racing tire. I went with a 31 spline up grade racing/street axle, and because I've had very good luck with Ford racing products, I went with the 31 spline Cobra differential from American Muscle. I opted for a racing specialty axle and have had to engineer the ABS system , so that it still operates. So if you want to do this upgrade be sure to ask if the new axles accept the factory ABS rings, other wise, know going in, that if you upgrade with specialty axles, you may loose your ABS system. No big deal, but be advised.


      Year: 2002 Submodel: GT St. Louis, MO

      Helpful (4)

    • 4/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      May 20, 2013

      Good solid LSD

      I have put this thing through the ringer at the track on full drag slicks and it is holding up like a charm.. Install was done by a local speed shop, but really is not hard to do if you are the wrenching type. Well worth the money.


      Year: 2005 Submodel: GT Valparaiso, IN, USA

      Helpful (4)

    • 5/5

      July 06, 2011

      31 spline diff

      worked and fit great, i would use this again if the time comes


      Year: 2002 Submodel: GT

      Helpful (4)

    • 5/5

      August 03, 2016

      Peace of Mind.....

      I had this diff installed with Ford Racing 4.10's and love it. You can't beat it for the price and it handles the extra torque the 4.10's throw at it and then some. If I could put it in one word I would say "SOLID" My mechanic told me I picked a GREAT diff for my set up which made me feel REAL good. Thanks AM! You guys Rock!


      Year: 2006 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $1000+

      August 05, 2015

      Ford Racing Limited Slip with Ford Racing 3.73

      Replaced what I believe was a stock limited slip diff with this since the stock one was wearing out and squealing/moaning. Since I was getting this done, I went ahead and did the whole rear end, put in 3.73 gears and new rear axles to go from 28 spline to 37 spline for this. Was a bit of a pain because I have the ABS option on the car but got the right axles for that and the shop got it in. I must say, the rear end is completely quiet now and feels like I got more power. The mechanic that installed the parts said he was really pleased with how everything went together so smoothly and perfectly. Feels great and sounds perfect again.


      Year: 1998 Submodel: GT California

      Helpful (2)

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