Yukon Gear & Axle Yukon Gear 1999-2004 Mustang Axle Kit, 31 Spline, 5 Lug, w/ Duragrip Positraction
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Yukon Gear 1999-2004 Mustang Axle Kit, 31 Spline, 5 Lug, w/ Duragrip Positraction

YUKYA FMUST-4-31
883584215592
Axles
20+ Units In Stock - Ships Next Business Day
$ 1,099.89
$ 1,099.89

Yukon Gear 1999-2004 Mustang Axle Kit, 31 Spline, 5 Lug, w/ Duragrip Positraction

Yukon Gear part YA FMUST-4-31 is a complete axle kit engineered for 1999-2004 Ford Mustang models with the 8.8in rear differential, including GT, Mach 1, and SVT Cobra. This kit upgrades to 31-spline, 5-lug axles paired with a Duragrip positraction unit, built from high-quality alloy for stronger-than-stock performance.

Key Features

  • 31-spline upgrade axles (left and right)
  • 5-lug bolt pattern
  • Includes Duragrip positraction unit
  • High-quality alloy construction with advanced heat-treating

Fitment

Year Make Model Trim
1999-2004 Ford Mustang Base / GT
2001 Ford Mustang GT Bullitt
2003-2004 Ford Mustang Mach 1
1999, 2001, 2003-2004 Ford Mustang SVT Cobra
2000 Ford Mustang SVT Cobra R

Specifications

Detail Value
Manufacturer part number YA FMUST-4-31
Application Ford Mustang 8.8in rear differential
Spline count 31
Bolt pattern 5 lug
Positraction unit Duragrip included

What's Included

  • Left and right 31-spline axle shafts
  • Duragrip positraction unit

About Yukon Gear

Yukon Gear & Axle manufactures differential, axle, and drivetrain components engineered for durable, precise-fit replacement and upgrade applications.

FAQ

What is included in this kit?

This kit includes left and right 31-spline, 5-lug axle shafts and a Duragrip positraction unit.

What vehicles does this kit fit?

This kit fits 1999-2004 Ford Mustang models with the 8.8in rear differential, including GT, Mach 1, and SVT Cobra.

What is a Duragrip positraction unit?

Duragrip is a limited-slip differential unit that improves traction by distributing power between both rear wheels.

Is this an upgrade from the stock spline count?

Yes, this kit upgrades many stock Mustang axles to a stronger 31-spline configuration.

Is professional installation recommended?

Yes. Installing this kit requires differential disassembly and precise setup, and should be performed by a qualified technician.

Can I use this kit for street and track driving?

Yes, this kit is designed for stronger-than-stock performance on the street and at the track.

Does this kit include gears?

No, this kit includes axles and the positraction unit; ring and pinion gears should be ordered separately if needed.

Do I need to confirm fitment before ordering?

Yes. Confirm your exact Mustang model and year before ordering.

Installation Instructions

  1. Remove the differential cover and carrier assembly.
  2. Remove the old axles and open differential carrier.
  3. Install the Duragrip positraction unit and new 31-spline axle shafts.
  4. Reassemble the carrier and torque all fasteners to specification.

WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Request For Information

Have questions about Yukon Gear 1999-2004 Mustang Axle Kit, 31 Spline, 5 Lug, w/ Duragrip Positraction? Fill out the form below and we'll get back to you by the next business day.
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