Steeda Autosports

Steeda S550 Mustang Threaded Differential Through Bolt Upgrade Kit (2015-2022)

 555 4051

In Stock - Less than 5 available

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Upgrade your S550 Mustang IRS differential hardware with Steeda's all new through Threaded Differential Bolt Upgrade Kit. Through bolting the rear super 8.8" differential to the IRS subframe on S550 Mustangs has become a popular modification due to premature bolt failure. Rather than permanently modifying your subframe by drilling out the bushings and differential housing, Steeda designed and machines in house a custom high strength hardened bolt that completely threads through the system. Post heat treatments the machined parts are nickel plated to prevent galling and provide superior corrosion protection. Using heat treated 4130 Chromoly steel, these custom bolts are as strong as a class 12.9 fastener and have been proven to last on some of the quickest and fastest S550 Mustangs out there, including Steeda's Silver Bullet.

Steeda's S550 Mustang THRU Threaded Differential Bolt Upgrade Kit is a must for all performance enthusiast looking for some bolt-in peace of mind.

Intended to be used in conjunction with our all new 555-4050 - Steeda HARDCORE S550 Mustang Differential Brackets.

Product Benefits
  • No permanent modification
  • Custom designed for this application
  • Nickel plated to prevent galling
  • Upgraded hardware over OE
  • Heat treated 4130 Chromoly for similar strength to grade 12.9 hardware

warningWARNING: California Residents: Cancer and Reproductive Harm;

Installation Difficulty:
Tools Required:
Basic Shop Tools
Estimated Install Time:
(approx.) 4 Hours
Vehicle Fitment:
2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023
Vehicle Trim:
Vehicle Trim:
Vehicle Trim:
Vehicle Trim:
Vehicle Trim:
Mach 1
Made in the USA
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  • Over 35 Years in Business