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Ford Performance IRS Ring Gear and Pinion Kit - 4.09 Gears (15-18 All)

Market Price $328.99 You Save 12% ($39.02)
Our Price

$289.97 (kit)

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  • Item 399248
  • MPN# M-4209-88409A

In Stock Ships same business day. Choose options to add to cart

Features & Details

  • Made for Street and Track Use
  • 4.09:1 Gear Ratio
  • 8.8" Ring Gear Diameter
  • Made from Premium Forged Material
  • Requires Professional Installation
  • Warranty Not Included
  • Fits All 2015-2018 Ford Mustangs
Boosts Performance. With the Ford Performance IRS Ring Gear and Pinion Set, you can feel a noticeable improvement in your Mustang’s engine performance and fuel efficiency. Indeed, its gear ratio allows you to accelerate faster and perform even better whether you’re on the street or on the track.

4.09:1 Gear Ratio. This ring gear and pinion set is truly the performance driver’s gear set. It comes with a 4.09:1 gear ratio which helps increase the performance of your car while maintaining its overall efficiency. It also helps your Mustang accelerate much more rapidly without the need to consume more fuel.

Highly Durable Construction. This high-quality IRS Ring Gear and Pinion Set has been manufactured out of highly durable forged steel which ensures long-lasting and quiet performance. It’s also coated with a corrosion-resistant black oxide finish for extra durability.

Recommended Upgrade. We recommend using a handheld tuner to recalibrate your Mustang’s speedometer after changing the rear axle gear ratio of your car. This is to avoid acceleration issues from miscalibration.

Attention 2010 and Newer Mustang Owners. Ford changed the inner rear gear pinion bearing in all 2010 and newer Mustangs with an 8.8-inch rear gear pinion bearing. To properly install this set, you will need a new 8.8-inch rear gear pinion bearing (Ford part# 9L3Z-4630-A). Please see drop down option above for more information.

For Professional Installation. Installation of this IRS Ring Gear and Pinion Set can be complicated. Which is why AmericanMuscle recommends getting the help of someone with mechanical experience to properly install this set on your Mustang. For best results, follow the included instructions.

Warranty. This product is sold “as is” and is available without any warranty from the manufacturer.

Application. This Ford Performance IRS Ring Gear and Pinion Set has been designed to fit all 2015-2018 Ford Mustangs.

Fitment: 2015 2016 2017 Details

What's in the Box
  • (1) Ring Gear
  • (1) Pinion Gear
Installation Info
Will it fit my Mustang?
  • V6 - 15, 16, 17
  • GT - 15, 16, 17
  • EcoBoost - 15, 16, 17
  • GT350 - 16, 15, 17

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Customer Reviews (1) Write a Review

Overall Rating 5.0

out of 5 stars

Installation Time:Afternoon

  • Performance Gain 3 3
  • Fit 4 4



  • 5/5

    Installation Time: Afternoon

    November 30, 2017

    Grate

    Was a bit iffy on getting because it’s going on my daily but I’m honestly really glad I got this

    Kevin

    Year: 2016 Submodel: GT

    Helpful (0)

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