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SR Performance 8.8 Axles - 31 Spline 5 Lug (99-04 GT, Bullitt, Mach 1)

Item 525037
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Ship to: Ashburn - 20149
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      Product Information

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


      • 1541H High Manganese Steel Alloy
      • 31 Spline Axle
      • 5 X 4.5" - Five Lug Design
      • 30.630" Axle Length
      • Kit Includes Driver and Passenger Side Axles
      • Bearings, Seals and Studs Also Included
      • Fits 1999-2004 GT, Bullitt and Mach 1 Mustangs with 8.8" Rears


      Performance Upgrade. If your running a heavily modified or forced induction New Edge Mustang, your factory 28-spline axles might be too weak to take the additional punishment. But after installing a set of SR Performance 31-spline 1541H alloy steel axles you will be sure to get all your pony's power and torque firmly planted to the pavement - where it belongs.

      Built to Out Perform. SR Performance Axles are forged from premium quality 1541H high manganese steel alloy that is induction heat treated for an axle shaft that is stronger and much more durable than stock, making it perfect for high stress street and race applications.

      Application. This pair of SR Performance 5-Lug 31 Spline Axles are specifically designed for use on 1999 to 2004 GT, Bullitt and Mach 1 Mustangs that have upgraded to a 8.8" 31-spline LSD or Spool only.

      Application Note: 1979-2004 V8 Mustangs came factory equipped with 28 spline axles, except for 2003-2004 SVT Cobras which were 31 spline.

      SR Performance

      Fitment: 1999 2000 2001 2002 2003 2004 Details

      MPN# 525037

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (8)

      Write a Review

      Ratings Summary

      5 out of 5 overall rating from 8 customers

      Installation Time: Afternoon

      • September 02, 2019

        5 1999 GT - NickA Installation Time: Less than 1 Hour

        What an upgrade!

        Was upgrading my gears and carrier and thought why not replace the axles. These axles make a huge difference when driving. They put the power to the ground with great grip and acceleration. Highly recommend.

        Helpful (0)
      • October 02, 2017

        5 2002 GT - BobStacy Installation Time: Less than 1 Hour

        31 spline axle

        I upgraded from my broken 28 spline to the sr 31 spline axles and I'm throughly impressed with quality and service.

        Helpful (10)
      • September 07, 2017

        5 2000 GT - MarcB


        was doing ring and pinion, bought everything to rebuild the whole rear end, these axles are better than stock.

        Helpful (12)
      • August 29, 2017

        5 2003 GT - Christian Installation Time: Afternoon

        Buy these

        Fit as they should, bearings fit correctly, would buy again if i had to

        Helpful (10)
      • August 11, 2017

        5 2001 GT - RD


        Have not installed three yet need more stuff to complete project. And adding more as I go

        Helpful (11)
      • March 11, 2016

        5 2003 GT - Smitty2000441 Installation Time: Afternoon

        Sr. performance axles

        Perfect fitment great quality easy instaliton great choice switch from factory 28 spline glade i did

        Helpful (11)
      • July 18, 2014

        5 2003 GT - Jorge18 Installation Time: Afternoon

        Solid product

        Everything looks perfect until I have to take out the abs ring out, but other than that very good I have lots of traction on my wheels

        Helpful (10)
      • June 20, 2014

        5 2001 Bullitt - RiceSucks Installation Time: Full Day


        Upgraded my dif to 31 spline these axles haven't given me any problems and fit good

        Helpful (12)

      Questions & Answers (3 answers)

      3 Top Rated Questions

      What is the warranty on these axles

      • These have a 30 day warranty.

      Helpful (0)

      Do you have to shim the brake calipers out with these? I've heard of that issue with one of the other major axle brands for the same application.

      • No, the brake calipers will not need to be shimmed however you would need a new diff with 31 spline spider gears to install these.

      Helpful (0)

      Will the factory ABS tone rings fit on these SR axles? The Moser axles specifically state that they will, but the SR axles do not.

      • I'm pretty sure AM would state in their description that you'd need different ABS rings if that was the case. The only time I've seen AM not inform you about other parts needed it's been because they didn't know at the time. I'm sure they're fine. I'm buying them right now and I don't expect to have any trouble.

      Helpful (0)
      Post Your Question

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (2) 31 Spline Axles
      • (10) Wheel Studs
      • (2) Outer Axle Shaft Bearings
      • (2) Seals

      Tech Specs

      • Splines: 31
      • Type: C-clip
      • Stud Pattern: 5 x 4.5"
      • Stud Type: 1/2" Press in
      • Length: 30.630 in
      • Material: 1541H alloy steel

      Will It Fit My Mustang

      • Bullitt - 01
      • GT - 99, 00, 01, 02, 03, 04
      • Mach 1 - 03, 04

      Fits 8.8" rear gears with 31 spline LSD or Spool only

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