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Ford Performance 3.73 Gears and Install Kit (10-14 V8; 11-14 V6)

Item 100573
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      Review & Installation Video

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Money Saving Combo Kit
      • Ford Racing 3.73 Gears - 8.8"
      • Ford 8.8in Rear Gear Pinion Bearing
      • Motive 8.8" Rear End Installation and Bearing Kit
      • 1 Bottle of Ford Racing Friction Modifier
      • 2 Quarts of Royal Purple Max Gear 75w140 Gear Oil
      • Fits 2005-2014 V8 and 2011-2014 V6 Mustangs with 8.8" Solid Rear Axle


      Improve ET's and low end torque. Are you looking to get more low end grunt off the line and lower ET's at the same time? Then look no further than installing a set of steeper gears in your Pony. This Ford Racing Ring and Pinion Gears are perfect for street, road, or race use.

      Complete Kit. This Ford Racing Gear and Installation Kit comes complete with all the components needed to swap out your ring and pinion gear. It includes Ring gear, Pinion gear, inner rear gear pinion bearing, 1 bottle of Friction Modifier, 2 bottles of 75w140 Gear Oil, gaskets, seals, shims, bearings and all the required hardware.

      Legendary Ford Racing Quality. When you're adding performance parts to your Pony, you can't go wrong by installing parts from the folks that know it best. Ford Racing's legendary quality ensures years of hassle-free use.

      Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a Ford Racing Speedometer Recalibration Tool or a Bama SF4/X4 Power Flash Tuner is a quick and easy way to fix this issue.

      Application. This Ford Racing 3.73 Rear Gear and Installation Kit is designed for use with 8.8in solid rear axle equipped Mustangs, including the 2005-2014 GT, Bullitt, BOSS, Shelby GT500 and 2011-2014 V6 models.

      Application Note: Does not fit 2013 Boss or 2013-2014 Shelby GT500 Mustangs with axle codes S-215-D and S-219-D.

      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.

      Fitment: 2010 2011 2012 2013 2014 Details

      Ford Performance 100573

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (87)

      Write a Review

      Ratings Summary

      4.7 out of 5 overall rating from 87 customers

      Installation Time: Weekend

      Installation Cost: $250-$500

      • April 23, 2020

        5 2013 V6 - BenJammin Installation Time: Shop Install Installation Cost: $500-$1000

        ford performance

        wow what a difference from the stock 2.73 ratio. did notice loosing a few mpg's but that could be due to driving it harder because its just so much fun now!

        Helpful (4)
      • February 08, 2020

        4 2014 GT - ThomasG Installation Time: Shop Install Installation Cost: $500-$1000

        BIG performance gain

        Awesome bang for the buck. Had 3.15 stock gearing and only CAI and tune for mods. Car is automatic. Installed by my local mechanic for $600. this REALLY woke up the car. seems to always be in the right power band and is much more responsive. for a sub $1k performance mod, I am extremely happy. on downside was driving slow for 200 miles during break-in period! highly recommend this kit.

        Helpful (6)
      • November 11, 2019

        5 2014 V6 - JimG Installation Time: Shop Install Installation Cost: $250-$500

        3.73 gear swap

        Just had a shop install these in my '14 v6 auto and what a difference. Now I can run on the highway in 6th gear and still accelerate, not sluggish in 6th any more. After I left the shop I did a launch in 1st gear, manual gear selection and I almost passed out it was so quick, was able to chirp the tires for the first time.

        Helpful (6)
      • August 24, 2019

        1 2014 V6 - nothappyatall Installation Time: Afternoon

        complete junk and no warranty

        Let me start by saying I am a Master Tech. I cannot get a good pattern on this gear set. I can get almost a good pattern but no contact in the middle no matter what i set the pinion depth or backlash at. When requesting warranty i was referred to Fords web site and found that Ford Performance parts are sold "as is" with no warranty, NO WARRANTY AT ALL. Now i have a $300 boat anchor.

        Helpful (8)
      • May 22, 2019

        5 2011 V6 - JayB Installation Time: Shop Install Installation Cost: $500-$1000

        So much for 1st gear

        I have been driving my V6 around with this kit installed for about a month now and I'll tell you what....forget you even have a 1st gear. It's totally useless. I also had the driveshaft upgraded and a dyno tune. I actually saw my city fuel mileage go up since I cruise around in 5th or 6th gear instead of 3rd or 4th. Hwy mileage only went down to about 28mpg. It turns out, the speed shop I went to for the install recommends to replace the MT-83 transmission down the road with a T-56XL. AM has one but only for the GT. The V6 version has slightly different gear ratios, idk if there are any other differences. Definitely an expensive upgrade but in the event of a messed up trans from track day driving, probably worth it, plus you'd gain a small amount of fuel mileage back since both 5th and 6th are OD gears in the T-56XL.

        Helpful (10)
      • November 12, 2018

        5 2013 GT - LukaszF Installation Time: Weekend

        Great mod!

        I was planning on upgrading my 3.15 gears to 3.73 after winter in the summer. However, my car had other plans. I developed some whining and issues with the rear. Instead of fixing the issue which would have been way cheaper. I decided since I am going to open it up I might as well upgrade. I have a few things to mentions if you are doing it yourself. This job is indeed a very messy job and requires a lot of work. We had done it on jacks, but I recommend finding a shop that can do it for a fair price. It is truly not worth doing it yourself. Also, you will need many specialty tools. Many of which you have to rent and some I had to purchase. Even with the right tools, there is still a lot you have to improvise yourself. Another mention is that you will need to buy a third bottle since you need to lube up the bearings as well as fill up the differential. Unfortunately, when I was purchasing these gears this kit was out of stock. American muscle was only missing the modifier which you don't need since royal purple has it already in it's formula. And they refused to send me the rest of the kit so I had to pay a lot more money to piece it together. When it comes to performance the car pulls very hard specifically if you have a tune on the car. I was quite surprised how the car had improved. I would recommend this mod hands down, but you really have to decide if you want to install it yourself.

        Helpful (22)
      • August 09, 2018

        5 2014 V6 - GeorgeS

        A must mod for a V6

        My 2014 is a completely different Mustang after having the 3.73 gears installed and a Bama tune. Super fun to drive now. Thanks American Muscle!

        Helpful (20)
      • July 29, 2018

        5 2013 GT - WilliamC Installation Time: Shop Install Installation Cost: $1000+

        great gears

        Gears went in no problem. Tuned it after I had it installed and made a huge difference

        Helpful (14)
      • July 21, 2018

        5 2014 V6 - battlezack Installation Time: Shop Install Installation Cost: $250-$500

        Must buy

        Bought gears back in 2016 December had Ford's techs install them if u have a mustang v6 u will love what these 3.73's gears does for your v6 outstanding performance and excelleration from a stand still I highly recommend the 3.73 gears would also recommend getting a tune or calibration tool for speedometer

        Helpful (18)
      • May 12, 2018

        5 2014 V6 - NathanC Installation Time: Shop Install Installation Cost: $250-$500

        One of the best mods!

        Highly recommend for that edge over others. The response is much quicker. That being said a few tips when getting them installed...1) You are going to need an additional quart of the royal purple oil to fill it correctly 2) do not forget there's a break in period that is recommended. You should drive for about 20-30 minutes then let it cool. And repeat the process several times before opening it up full throttle. 3) The speedometer will be off. Mine was 15mph faster than actual speed and I've seen others including mine become even more inaccurate the faster you go. Over all great product for the price!

        Helpful (21)

      Questions & Answers (28 answers)

      5 Top Rated Questions

      I am thinking about upgrading to this kit for my 2012 GT. It currently is running on a tune 24/7 because of my boss 302 intake and it is tuned for the stock 3.15 gears. I plan on having this done professionally, I will get a new tune for these 3.73 gears before i take it in. Should i tell the shop not to start the car until i have the new tune for these gears installed?

      • Naw it will be alright your speedo will be off by a few mph's that's all. If you have a manual car I would go 4.10 only if you don't drive it ever day with that 6 gear you almost can't tell. I got that in my car now and let me tell you it's amazing out of the gate......

      Helpful (11)

      "Ford Performance 3.73 Gears and Install Kit (10-14 V8; 11-14 V6)." Hi, i bought these for my 14 v6, still in the box. I'm thinking about purchasing a 17 v6, will this gear kit fit in the 17 v6? Thx

      • This Ford Racing 3.73 Rear Gear and Installation Kit is designed for use with 8.8in solid rear axle models and will not work with the 15+ models due to the independent rear end.

      Helpful (2)

      would these gears fit my stock carrier from my 2014 mustang v6 premium that carried a 2.73?

      • This certainly would fit your 14 V6.

      Helpful (2)

      Hi, I have Gt 2011 with stock gears 3.15 my question is wich one is better in drag racing from 0 KM , 40 KM , and 60 KM the 3.55 or 3.73 ? Thanks.

      • The Ford Performance 3.73 Gears and Install Kit will be able to get you off the line much faster than the 3.55 gears will. However, the 3.55 gear ratio will keep pulling at higher speeds than the 3.73s for a longer stretch.

      Helpful (1)

      if I were to install these gears would I need to get new axles as well or will stock axles work just as good?

      • The Stock axles will absolutely work with the Ford Performance 3.73 Gears and Install Kit without any issues.

      Helpful (1)
      10 More Questions
      If I purchase this kit for a 2010 GT, do I still need to purchase the "Rear Gear Pinion Bearing" Item#394003? I remember seeing a video here on AM, and Steph said this would be necessary for the 2010 because the design had changed. Or is there a complete kit for the 2010's specifically? 1 answer
      I have a base model 2014 v6 with 120k miles, im sure the gears are 2.73 and I was wondering does this kit have everything I need to change it to 3.73? 1 answer
      Is it recommended to buy a new drive shaft with this? Also if I just change my gears will I have problems down the road for going so fast? 0 answer
      I have a slightly modified 2012 gt Mt with 3:31’s now. Looking to upgrade to 3:73 or 4:10. It’s just a weekend toy so not worried about gas mileage or anything. Looking for opinion on witch might be better choice. Leaning towards 4:10s but don’t want 1st gear to be useless! Any opinions would be helpful thanks! 0 answer
      For my vehicle and set up, 2014 V6 mustang what would be better 3.55 or 3.73 gears I'm am running a custom tune on 91 premium gas, and looking for a little bit better fuel economy. So what would be the better option for my setup 1 answer
      what's the weight of "Ford Performance 3.73 Gears and Install Kit" package? 1 answer
      I have a 2013 V6 3.7L will this be ok to install and drive on every day? 1 answer
      Will this kit work with a six speed manual Mustang 2012 V6? 0 answer
      Putting these in a 14Gt... Do I need to do a tune when you re-gear? 1 answer
      I can't find a shop in my area that will install this for a reasonable price. If I brought my car to you guys could you install it? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Ring gear
      • (1) Pinion gear
      • (1) Rear Gear Pinion Bearing
      • (1) 3.8 fluid oz bottle of Friction Modifier
      • (2) one quart bottle of Royal Purple Max Gear 75w140 Gear Oil
      • Front & Rear Pinion Bearing
      • Pinion Seal
      • Carrier Bearings
      • Carrier Shims
      • Differential Bearings
      • Crush Sleeve
      • Pinion Nut
      • Cover Gasket
      • Ring Gear Bolts
      • Brush
      • Gear Marking Compound
      • Loctite

      Will It Fit My Mustang

      • Boss 302 - 12, 13
      • GT - 10, 11, 12, 13, 14
      • GT500 - 10, 11, 12
      • V6 - 11, 12, 13, 14

      Does not fit 2013 Boss or 2013-2014 Shelby GT500 Mustangs with axle codes S-215-D and S-219-D.

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