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Ford Performance IRS Ring Gear and Pinion Kit - 3.73 Gears (15-18 All)

Market Price $224.99 You Save 12% ($27.00)
Our Price

$197.99

FREE Shipping
  • Item 384403
  • MPN# M-4209-88373A

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

Features & Details

  • Ford Racing Quality
  • Strong Forged Construction
  • 3.73 Gear Ratio
  • 8.8" Ring Gear Diameter
  • For Street or Track Use
  • Fits 2015-2018 Mustangs Equipped with IRS
Upgrade OEM Gears. Are you looking to upgrade to a stronger set of rear gears? Then look no further than installing a set of genuine Ford Racing Gears in your 2015-2018 S550 Pony. Ford Racing Ring and Pinion Gears are perfect for street, road, and race applications.

Superior Quality. Manufactured in the USA, these Ford Racing Mustang ring and pinion gears feature a super strong forged construction, CNC cut & lapped gear teeth, and are completed in a black oxide finish to resist corrosion.

Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a Mustang Handheld Tuner is a quick and easy way to fix this issue.

Application. This 3.73:1 Ratio Ford Racing Ring and Pinion Gear set will fit all 2015-2018 Mustangs equipped with an 8.8" Independent Rear Suspension (IRS), including V6, EcoBoost and GT models. A master bearing kit is recommended by most installers, especially on high mileage vehicles.

Application Note. These Ford Racing 3.73 gears are not compatible with a 3.15 ratio differential - use differential M-4204-MT or M-4204-M.

Technical Note. Installation costs will vary, but a good rule of thumb is between $250 and $300. Be sure to work with a reliable shop that you trust for installations.

Fitment: 2015 2016 2017 Details

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

These 3.73 gears are not compatible with a 3.15 ratio differential - use differential M-4204-MT or M-4204-M.

People Who Bought This Item Also Bought

Most Helpful Reviews

3/5
poor communication

not happy ..did not know that i had to order bearings and shim kit ..my car is now stuck at the service center till missings parts arrive ..would have been nice to have a heads up that this stuff needed ...

Read More
Helpful (8)

5/5
Ford Racing IRS 3.73 Gears Set

Wow! Coated and hardened as well, this gear set is pristine boxed and packaged well no need to worry about any damage of any kind during shipping comes with crush sleeve and pinion nut. Be sure to take ...

Read More
Helpful (3)

Overall Rating 4.6 out of 5 stars
Read All 7 Reviews

Customer Photos

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29 Questions / 6 Answers

Ask a Question

I have a 2016 ecoboost 8000 miles What do I need to change gear ratio I think I have 3.35 now I was thinking 3.73 what do you think

JB

  • As long as you do not have the 3.15 gear ratio, all you would need would be the ring and pinion!

    Ricky36

Helpful (1)

Does a swap to this gear require a tune. I'm currently running cobb's stage 1 tune on my ecoboost.

Jim

  • Hello! This will not require a tune to run on your vehicle, however we definitely recommend updating your tune, otherwise the calibration of your speedometer will be off!

    Doug P

Helpful (1)

So I have a 2016 ford mustang v6 and was told it has the 3.15 axle ration by the dealer "I bought it new" but it always spins both tires. Never once has only one wheel spun. I was reading the 3.15 ration wasn't limited slip. Is this correct

NicholasS

  • The factory gear ratio would not affect if the vehicle was limited slip or not. You cna give your VIN to a Ford dealer who will be able to tell you if a limited slip was installed, however most modern Mustangs came with a limited slip as standard equipment

    Rob D

Helpful (1)

So I will need an entire. Rear career to swap in 3.73 gears over my 3.15s in my 16 v 6 mustang

Cecil

  • Yes, you will need a new center carrier to put 3.73s in a Mustang that had 3.15s from the factory.

    AMSam

Helpful (1)

What is better for my 2015 auto gt with 3:15s? 3:55 or 3:73

jab2636

  • Both 3.55s and 3.73s will be a great gear set. However the best one would depend on your driving. If you drive mostly highway I would go with the 3.55 as they are a longer gear. If you do not drive a lot of highway then the 3.73 would work well since they are a shorter gear.

    Ricky36

Helpful (1)

I have 3.15 gears in my 2015. I want 3.73. I want to know what all i need to do the swap before i tear down. Car has low miles and a supercharger with about 100 miles on it.

SuperGT

  • You're better off purchasing the gear and pinion set with installation kit so everything is new. It's recommended the bearings are replaced instead of using the old ones! Other than that and gear oil, That's it! By the way, If you're asking this question, Then I'm assuming you're taking it to a mechanic that knows what he's doing, Gear installs are not just remove and install, You need to get the correct backlash so get it professionally installed!

    Rush

Helpful (1)

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Customer Reviews (7) Write a Review

Overall Rating 4.6

out of 5 stars

Installation Time:Afternoon

  • Performance Gain 4.857143 4.9
  • Fit 5 5



  • 3/5

    August 25, 2017

    poor communication

    not happy ..did not know that i had to order bearings and shim kit ..my car is now stuck at the service center till missings parts arrive ..would have been nice to have a heads up that this stuff needed to order seperetly ..not pleased

    WayneG

    Year: 2015 Submodel: GT

    Helpful (8)

  • 5/5

    Installation Time: Full Day

    May 02, 2016

    Ford Racing IRS 3.73 Gears Set

    Wow! Coated and hardened as well, this gear set is pristine boxed and packaged well no need to worry about any damage of any kind during shipping comes with crush sleeve and pinion nut. Be sure to take your time during install if you're doing yourself! Follow downloadable instructions for video tutorial tutorials to the T and do not take any shortcuts. Be absolutely sure and double check your backlash and gear mesh markings with either the marking compound that comes with a gear install bearing race and shim kit, if not occasionally I will use regular bearing Grease. Then be amazed what a difference from 3:31 to the 373. Day-to-night difference in acceleration and a lot quicker through each gear definitely going to help in my 8 Mile and quarter mile times, and also get rid of the lag and Bogg that 6 gear has on the highway and eliminate having to shift into 5th to accelerate around someone. I'm definitely going to enjoy this for a long time, I searched and searched for a set of 4.10's but just was unable to find... but anyway I'm extremely happy with the 373 s 4 they're definitely going to save me on gas money and mileage and come to many Smiles per gallon thanks American Muscle your speed eaters and shipping is the best. Ray Ulrich

    RayRayStang

    Year: 2015 Submodel: GT

    Helpful (3)

  • 4/5

    May 28, 2017

    ring gear

    means I have to get 5 pieces for each ger is one kit??

    aloa

    Year: 2015 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    October 17, 2017

    gears

    excellent product fit well had gears installed bye dealer ..very happy

    WayneG

    Year: 2015 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Afternoon

    September 01, 2017

    GT 350 gears

    What a great mix between street, highway, and strip. Easy installation. Noiseless and strong. Great product.

    Jangle

    Year: 2016 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Full Day

    July 04, 2017

    Make sure to change the chunk

    This is the best mod by far it gives you that pushed back in the seat effect just maybe sure if you change to a bigger gear you will need to change the chunk out

    Stang435

    Year: 2015 Submodel: V6

    Helpful (0)

  • 5/5

    June 10, 2016

    Fast shipping

    All can review on this item is the wonderful service by AM once again. All the shops near me are booked for the next 3 weeks so there not in yet. Thank you AM!

    Tallica4lilfe81

    Year: 2016 Submodel: V6

    Helpful (0)

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