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

Item 24062
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      Review & Installation 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

      Product Information

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


      • 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


      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

      MPN# M-4204-F318C

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (94)

      Write a Review

      Ratings Summary

      4.8 out of 5 overall rating from 94 customers

      Installation Time: Full Day

      Installation Cost: $250-$500

      • February 24, 2020

        5 2012 GT - gilly5oh Installation Time: Full Day


        feels like a totally different car. Highly recommended if your switching gears

        Helpful (0)
      • December 17, 2019

        5 2008 GT - Fbmustang2008 Installation Time: Afternoon

        Easy to install

        Great product! OEM quality. Never installed one of these before, completed in an afternoon inside of garage. Put on 2008 Mustang GT/CS with over 250,000 miles on original diff, made since to put an OEM back in. Ordered the Ford Performance Ring and Pinion Installation Kit w/ High Torque Bearing - 8.8 in. (11-14 V6; 86-14 V8, Excluding 13-14 GT500) to help with install. Had everything I needed, minus the gear oil (75w90, 3 qts) and friction modifier (1 small bottle). No improvement for performance, just no more "whine" every time I turn left or right.

        Helpful (1)
      • November 27, 2019

        5 2005 GT - JoeB Installation Time: Shop Install Installation Cost: $500-$1000

        Perfect OEM Fit

        I can already tell a difference between this and the stock limited slip. Car is more sure footed and both tires always engage when power is applied. Good buy for the price

        Helpful (1)
      • October 08, 2019

        5 2010 GT - DaveS197 Installation Time: Shop Install Installation Cost: $250-$500

        Fried old posi

        Had been noticing some problems with the original posi in my 2010 GT. Worn clutches making the car dance around on the highway, under acceleration and deceleration. Was going to change to 3.73's and noticed a great price on a new Ford posi so I purchased both. Car is nice and tight again and I'll be going to the track this weekend to check out the new gears.

        Helpful (2)
      • September 01, 2019

        4 2005 GT - GHanes

        Great product, wish it came w/ bearing

        Worked great as an upgrade and repair for my 05' GT, wasn't too hard to install either.

        Helpful (1)
      • July 18, 2019

        5 2013 V6 - LeoR


        Cool item to get made my car feel a lot more faster

        Helpful (1)
      • July 09, 2019

        5 2006 GT - 3VIL Installation Time: Afternoon

        works like a charm

        Replacing what was sneakily replaced with a junkyard one during a ring and pinon swap at the local race shop (turds). They basically stole my good chunk for their race car, I figured. New one has the standard clunk the factory one does but that's Trak-LOK for ya. no slip, just bite when I need it.

        Helpful (1)
      • June 12, 2019

        5 1995 GT - JudeB Installation Time: Afternoon

        Ford Performance Trak-LOK

        Product is exceptional! Put in my 95 f150 (lightning build). Great traction off the line and works great. Really livened up the rear end with tons of grip for that 351w to tear up F-Body Camaro’s.

        Helpful (0)
      • May 31, 2019

        1 1999 GT - 99Gtottawa Installation Time: Full Day


        In under 2500 km the case wore out and the pin to hold the spider gears slaps back and forth and makes a lot of noise, I’m worried about it breaking so I need to buy a new Posi, not buying this again! . Poor quality, would recommend buying eaton instead.

        Helpful (1)
      • May 05, 2019

        5 2005 GT - RonaldG Installation Time: Full Day


        This LSD has the features I need for the mild custom build I'm doing on our '05 GT convertible. I do thrash the throttle on a consistent basis so I need the extra protection from breakage.

        Helpful (1)

      Questions & Answers (67 answers)

      5 Top Rated Questions

      Ok, I have been looking at your website plotting all of what I am going to do to my GT. I need some help and advice all together. It is auto trans which I am swapping thats first. Then I want to put the 4.10 gears in it with an aluminum drive shaft now I dont understand what Spline means. And I am confused on do I need to switch my rear differential or what is stock in mine good for the set up? I am not a mechanic nor have any experience working on cars I know what I want mostly and am having a pro put it together I just want to order my own parts from here to know what im getting other than letting him decide. Please HELP. And I know ill have a million other questions through this process

      • The Ford Performance Traction-LOK Limited Slip Differential is designed to accept 31 spline axles, the driveshaft's spline count will not be affected by this. Spline count refers to the number of splines (the small "teeth" that mesh together for your axles or driveshaft) so a 31 spline axle will not fit into a 28 spline housing, due to a different number of teeth or splines. Depending on the year and model of your Mustang, you may have 28 or 31 spline axles. More info can be found at the link below:

      Helpful (6)

      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 (3)

      will i be leaving two lines on a burnout with this LSD

      • The Ford Racing Traction - LOK Limited Slip Differential w/ Carbon Discs - 31 Spline 8.8 in. (86-14 V8; 11-14 V6) will definitely give your Mustang a lot more traction. There will be no more one wheel burnouts with this Posi!

      Helpful (3)

      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.

      Helpful (3) Show 3 more answers

      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.

      Helpful (2)
      10 More Questions
      Will this be a straight swap to my differential or would I have to buy new splines , ring and pinion gears and bearings etc..? 1 answer
      Will adding this to a 2012 V6 Mustang help at all in the 0-60 and 1/4 mile? 3 answers
      My end state hp will be 650-700 hp for my 2008 Mustang GT, with Kenne Bell super charger. Would this more than adequately cover that hp range, or should I play it safe and get one of the other Ford Performance higher end diffs, like the T-2 Torsen or the FR500S? Thank you for you time. 1 answer
      Does this use a 7/8" or 3/4" crosspin? 1 answer
      If I have a 2014 V6 Mustang will this work with my stock axles? Or will I have to buy new axles? 1 answer
      Is this suitable for forced induction? Im rebuilding my drivetrain from a 28 to a 31, I plan on adding a supercharger in the future. Will this LSD support the power? 1 answer
      Is this a 2 way differential? If not do you guys sell one? 0 answer
      So I need to rebuild my rear end and I want to upgrade it in the process. If I get this, will it work with 4:10s and do i just use the preloaded tune for those 4:10 gears? 09/GT (stock rear end) 0 answer
      Will this work with 4.56 gears. 0 answer
      I currently own a 2014 V6 mustang, and I am looking to buy a 4.10 gear ratio for my car. Will this pair nicely with that gear ratio or should I invest my money into something else? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Limited Slip Differential

      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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