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SR Performance Ring Gear and Pinion Kit - 3.73 Gears (05-09 GT)

Item 397883G05
Market Price $159.99 You Save 22% ($35.00)
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    Features & Details

    • Perfect for Street and Track Use
    • 3.73 Gear Ratio
    • 8.8" Ring Gear Diameter
    • Premium Grade 8620 Triple Alloy Steel
    • Corrosion Resistant Black Oxide Finish
    • Professional Installation Recommended
    • Fits 2005-2009 GT Mustang Models
    Performance Improvement. Get your V8-powered GT up off the line quicker by installing a set of 3.73 SR Performance Ring and Pinion Gears. A steeper set of Gears will place your 2005-2009 GT into its power band much quicker for faster off the line acceleration and a noticeable increase in low end grunt. These 3.73 Gears are a great choice for both street and track applications.

    3.73 Gear Ratio. 3.73 gears are a great combination of performance and fuel economy that are ideal for a daily-driven Mustangs that see a lot of highway time. If you put a lot of miles on your Pony and don't want to increase your cost at the pump, a 3.73 ratio will still give you the added acceleration you want without dramatically compromising fuel economy.

    Quality Construction. SR Performance manufactures their ring and pinion gears from forged 8620 triple alloy steel for superior strength. Featuring CNC cut and lapped gear teeth, SR Performance completes their gears in a black oxide finish for long lasting corrosion resistance.

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

    Professional Installation Recommended. The installation of Ring and Pinon Gears can be a very intricate process, so mechanical experience is highly recommended. Follow the included instructions for best results.

    Application. This 3.73 SR Performance Ring and Pinion Gear set will fit all 2005-2009 GT Ford Mustangs equipped with a 8.8" rear end. A master bearing kit is recommended by most installers, especially on high mileage vehicles, see drop down option above.

    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. You can also save money on your installation labor by having your Trac-Lok rebuilt at the same time as your gears are installed, see drop down option above.

    SR Performance

    Fitment: 2005 2006 2007 2008 2009 Details

    MPN# 397883G05

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Ring Gear
    • (1) Pinion Gear
    Installation Info
    Will it fit my Mustang?

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        Questions & Answers (2)

        2 Top Rated Questions

        This will fit my 05 v6 mustang ? And my rear en is 7.5 or 8.8 ?

        I have Pony Package 06 that is stock 8.8" rear end so this should work, correct? I ask as your car selection tool does not have selection for the Pony Package which has a few GT upgrades on them.

        • The 3.73 SR Performance Ring Gear and Pinion Kit will fit the rear end of the 2006 Pony Package V6 Mustang.

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          Customer Reviews (4) Write a Review

          Overall Rating 4.8

          out of 5 stars

          Installation Time:Full Day

          • Performance Gain 4.25 4.3
          • Fit 4.5 4.5

          • 5/5

            Installation Time: Full Day

            September 02, 2019

            06 GT

            Great product, took about a day to do by myself in garage, can definitely feel the difference, went from 3.31 to 3.73 auto car


            Year: 2006 Submodel: GT

            Helpful (0)

          • 5/5

            Installation Time: Afternoon

            November 27, 2018

            Torque plus up!

            Gears set up nicely and are super quiet. It's a nice addition the my son's 99 Cobra. The 3:25 made it a little long legged and now with the 3:73 it's way more torquey.


            Year: 2006 Submodel: GT

            Helpful (9)

          • 5/5

            Installation Time: Full Day

            February 26, 2018

            Quality and Great Value

            Chose these as part of complete Diff rebuild on ‘08 Bullitt. I drive the car “48000” miles very hard. I rebuilt blown out Diff. The stock pinion splines we’re heavily worn. SR products are a great value. Combined Ford Racing Diff w/these 3:73s Getting the marks aligned took some time, so I recommend a good mechanic install. Nice upgrade for the price. Allowed me to add Ford Racing Cover to keep cool. Don’t forget to change axle bearings as well.


            Year: 2008 Submodel: Bullitt

            Helpful (17)

          • 4/5

            Installation Time: Full Day

            February 10, 2018


            Worth the money really woke up my car.. highly recommended!


            Year: 2009 Submodel: GT

            Helpful (14)

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