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Alloy USA 8.8 Axles - 31 Spline 5 Lug (05-09 GT, GT500)

Item 18958
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$259.99 (pair)

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    Features, Video & Details

    • 1541H Alloy Steel
    • 31 Spline
    • 5 X 4.5" - Five Lug Design
    • 10 Year Warranty!
    • Driver and Passenger Side Axles Included
    • Fits 2005-2009 GT and 2007-2009 GT500 Mustangs with 8.8" Rears

    Review & Installation Video

    Review & Install Video

    Hey, Justin with here, taking a closer look at the alloy USA 31 spline 8.8 axle kit, fitting all 2005 and newer GTs, all 2011 and newer V6's, and all 2007-2009 GT500s. Anyone who is hardcore into drag racing probably has a few stories to tell about experiencing a busted axle. The truth is the factory axles are fine for most but when you really start adding some horsepower and launching on a sticky tire, you run the risk of damaging or even breaking those factory axles. Speaking of which if you want to see us subject our project cars to a few quarter mile beat downs, you have to subscribe to our YouTube channel by clicking on the link below. This kit from Alloy comes with everything needed to eliminate those weak factory axles from the equation in your S197. The major players in this kit are the brand new 31 spline axles which have been made from a high quality alloy steel, using a unique heat treating process which basically just ensures a stronger, much more durable axle. Alloy then uses what's called a cold form, rolled spline process to process a spline that is roughly 35% stronger than a standard cut spline. Alloy stand behind this design so much that they include a 10 year warranty with every set of axles sold. If you want to hear more about what our customers are saying about using these axles in their own rides, you have to click the link below to head back to the product page at That kit does include the factory ABS sensors and even includes brand new wheel studs, bearings, and axle seals. Even though we always encourage our backyard mechanics to tackle almost any job, diving into the rear end and swapping axles can be a little tricky if you've never done it before, so that's why we recommend leaving this one in the hands of your local shop. On the other hand if you have no problem around the garage, just leave yourself about 4 hours from start to finish to get the job done. Either way if you have any questions about the fitment, the axles themselves, or about the install, don't hesitate to get in touch with one of our Mustang experts. So if you're serious about dragging your S197 and you want to eliminate the possibility of a busted axle altogether from the equation, then you might want to check out the Alloy 31 spline axle kit available right here at

    Performance Upgrade. If your Mustang is heavily modded or running a forced induction setup, your stock axles might be too weak to take the heat. These premium quality 1541H alloy steel axles will ensure that all the power and torque is transferred straight to the pavement - where it belongs.

    Stronger than OEM. Manufactured from high quality 1541H alloy steel using a computer controlled induction heat treatment that results in a stronger, more durable axle shaft. Alloy USA uses a cold-formed rolled spline process that produces an axle spline that is up to 35% stronger than standard cut splines.

    10 Year Warranty. These Alloy USA axles come with a 10 year limited warranty to be free of defects in material and workmanship from the date of purchase. Some limitations do apply. Please see the full Alloy USA Warranty disclosure for details.

    Application. This pair of Alloy USA 5-Lug 31 Spline Axles are specifically designed for use on 2005-2009 GT and 2007-2009 Shelby GT500 Mustangs that have the stock 8.8" 31-spline LSD installed.

    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.

    Fitment: 2005 2006 2007 2008 2009 Details

    MPN# 12189

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (2) 31 Spline Axles
    • (10) Wheel Studs
    • (2) Outer Axle Shaft Bearings
    • (2) Seals
    Installation Info
    Tech Specs
    • Splines: 31
    • Length: 31.688" / 32.813"
    • Type: C-clip
    • Stud Pattern: 5 x 4.5"
    • Stud Type: Press in
    Will it fit my Mustang?

      Customer Photos (3) Submit Your Photo

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        Questions & Answers (5)

        5 Top Rated Questions

        Are all of the components manufactured in the USA, to include bearings, seals and studs?

        • These pieces are sourced internationally.

        Helpful (0)

        Would these be compatible with a Torsen differential? T2 or T2R

        • As long as it is a 31 spline differential and 8.8" rear end, this should work with it.

        Helpful (0)

        compatible with 2008 V6? I am planning to upgrade by 7.5" V6 axle to 8.8". All the pre-assembled rear ones do not come with gears and differential locks that I am planning to put on for my racing. So can I use this kit along with gears and limited slip differentials for 8.8" to complete the upgrade? What else would I need?

        • Yes the axles would work with a 8.8" housing you would just need to purchase a Limited Slip Diff that supports 31 splines and some 8.8" gears like 4.10 or 3.93 etc. You can get everything you need from AmericanMuscle

        Helpful (0)

        About these axle replacements I want to know if these axles would be compatible with an auto trans

        • Yes, they will work with a manual and automatic.

        Helpful (0) Show 1 more answer

        ABS? Can the factory ABS sensors be relocated to these axles?

        • Yes, in fact that is what I did. It's not easy but it can be done. You need to heat up the rings with a torch then pry them off while being careful not to damage the teeth. To install them on the new axles I put the rings in my oven then hammered them on the axles with a brass punch.

        Helpful (0) Show 2 more answers
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          Customer Reviews (16) Write a Review

          Overall Rating 3.8

          out of 5 stars

          • 5/5

            November 10, 2019

            Great quality

            Looks awesome rides smooth no noise Great for hard launches!!!


            Year: 2007 Submodel: GT

            Helpful (0)

          • 4/5

            September 10, 2017

            Packaged wrong.

            Disassembled rear diff to install. Wheel studs were installed in axles already when I found out that the axles were both the same length!!! Lost 2.5 quarts of Royal Purple lube and friction modifier. Now in process of contacting A/M for correct axles and new studs or refund. Always have had good luck with A/M so hopefully this can be resolved.


            Year: 2009 Submodel: GT

            Helpful (10)

          • 4/5

            September 05, 2017

            Alloy Axles

            I purchased these axles as I had a bent one on my car. The axles went in and fit perfectly, but as many had mentioned the wheel studs are a little too short. I wasn't going to use the new ones and then install the axles to then find out they are too short. I went ahead and used my originals. Have had the axles on for about a month now and they ride great. Overall a great purchase.


            Year: 2007 Submodel: GT

            Helpful (10)

          • 1/5

            April 28, 2016

            Horrible replacements from stock

            My stock axles took several 6k rpm launches and finally bent and I chose these as replacements, decided to only launch at 3k rpm at the track and bent them within 10 launches... Horrible


            Year: 2009 Submodel: GT500

            Helpful (11)

          • 5/5

            September 24, 2015


            Product was awesome. Packaged nicely, short and long side were marked. Removed old tone rings and they fit snug on the new axles. Overall awesome product. Recommend to anyone


            Year: 2005 Submodel: GT WA

            Helpful (11)

          • 3/5

            June 14, 2015


            It was stressful trying to get the bolts on, although I had a proper mechanic do it I saw him struggling through the process.


            Year: 2014 Submodel: GT

            Helpful (12)

          • 5/5

            December 22, 2014

            Great Product

            I have had these axles on my car for 3 months now and they are great much firmer than stock if you are changing your gears out like I was you might as well change your axles while you got it all apart these are a perfect upgrade


            Year: 2011 Submodel: V6 Muskogee, OK, USA

            Helpful (11)

          • 1/5

            July 23, 2014

            Poor machining and lousy bearing and seals

            Bought a set and had installed at a well respected shop. After install took it for a drive and it sounded horrible like bad bearing or similar. (picture driving on huge offroad tires sound) I drove an hour total before having it torn back apart to investigate. Turns out the axles have machining marks and are out of round because of it. The seals were leaking after 1 hour and the bearings were already looking bad. Everything ended up getting ripped out and replaced with stock again. AM had Great customer service though. I would not waste chancing $500 in labour installing and removing to find out they have similar issues. Spring for the Moslers.


            Year: 2005 Submodel: GT Ontario, Canada

            Helpful (11)

          • 5/5

            May 05, 2014

            great axles

            These axles are a great upgrade for anyone planning on running drag radials. My car has the optional track package which comes with the boss 302 torsen differential so I ended up needing 3 bottles of gear oil(used royal purple), 2 bottles should be sufficient for a standard gt. I reused my old reluctor rings for the wheel speed sensors. It was fairly difficult to remove them from the stock axles, but a little heat and a big pry bar got the job done. The other major obstacle is installing the wheel studs which need to be pressed in. I used a hammer to pound them in instead of pressing. Not the ideal method but it was effective. Overall it was a fairly simple install that anyone with some mechanical ability can handle in their garage at home.


            Year: 2013 Submodel: GT Southaven, MS, USA

            Helpful (11)

          • 5/5

            April 03, 2014

            Needed stronger axles.

            Not having to worry about a bent or broken axle is nice. Did upper control arm and new carbon fiber traction rebuild at the same time. So the rear end seems so solid. My 600+ HP will not go to waste. As always American Muscle has the best products and quick delivery.


            Year: 2011 Submodel: GT Albuquerque, NM

            Helpful (11)

          • 4/5

            February 25, 2014

            gets the job done well

            Felt a reinforced feel when driving over bumps and can really feel safe now when I put the power down at the track and not have to worry about bending an axle


            Year: 2011 Submodel: GT Laredo, TX, USA

            Helpful (11)

          • 1/5

            January 27, 2014

            worst axles ever

            i have a 2013 with bolts on its and 11.80 car i was running fine with my stock axles i change the gears and i change the axles just for to be on the safe side with this alloy axles i made 2 passes and the driver side axle broke if you a drag your car once a while dont buy this product


            Year: 2013 Submodel: GT Miami, FL, USA

            Helpful (10)

          • 5/5

            December 20, 2013

            Great product

            Great you really can feel the differance there's no lagg and it's real easy to smoke the tires up !


            Year: 2013 Submodel: V6 Fresno, CA, USA

            Helpful (9)

          • 4/5

            November 07, 2013

            Solid replacement.

            I bent my stock axles the first time I went to the track after I upgraded my clutch. These went in along with new bearings and a new traction lock unit. Just to swap the axles only takes about 2 hours taking your time. They've held up great so far with street launches. I'll be anxious to get them on the track when the weather warms back up. You will NEED ABS RINGS to put on these if you have ABS. They are not included.


            Year: 2007 Submodel: GT Tuscaloosa, AL, USA

            Helpful (11)

          • 5/5

            September 11, 2013

            Great Axles

            I installed these axles a while ago, and have had 0 issues. ABS sensors were able to be transfered. Axles seemed stouter than my axles. I didnt use the bearing kit, my buddy (a certified mechanic) measured the diameter, and they were identical, no scaring or anything on old axle so we just reused old bearings/ seals, and have an extra set for if/when i have to do them. I got these axles because i had slightly bent my originals with some not correctly back spaced slicks. Slicks stuck out 2-3" past fender. The rear brakes started squeaking, upon putting it on a lift and running car up to speed you could see a slight runout. Replaced axles and everything is good.


            Year: 2012 Submodel: GT Denver, CO

            Helpful (11)

          • 3/5

            August 12, 2013

            Good price, poor fit

            Overall, if you're looking to save money- this product workswell. They required quite a bit of filing and grinding the center hub portion to fit stock 17" GT wheels as the wheel would not slide onto the axle as it should. The lugs do not come pressed in, so you'll need a press, or a sledge hammer to get them seated properly. Also, ABS tone rings are not included, so you'll need to remove your old from stock, and again, press onto the new. I was able to do all this as I have a 20 ton press in the garage, but these might not be for every home mechanic. Product works, but be aware of possible install snags.


            Year: 2007 Submodel: Other San Diego, CA, USA

            Helpful (9)

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