(approx) 4 Hours
Mechanical expertise or professional installation required.
- Differential Gears - Installation Instructions
Ford Performance 8.8-Inch Rear Axle Bearing and Seal Kit (05-14 V8; 11-14 V6)
Ford Performance Traction-LOK Limited Slip Differential with Carbon Discs; 31 Spline 8.8-Inch (11-14 V6; 86-14 V8, Excluding 13-14 GT500)
Ford Performance Traction-LOK Rebuild Kit with Carbon Discs; 8.8-Inch (11-14 V6; 86-14 V8, Excluding 13-14 GT500)
Features, Description, Reviews, Q&A, Specs & Installation
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 - www.P65Warnings.ca.gov
April 23, 2020
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
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
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
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
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
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
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
Gears went in no problem. Tuned it after I had it installed and made a huge differenceHelpful (14)
July 21, 2018
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 speedometerHelpful (18)
May 12, 2018
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)
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......
"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.
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.
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.
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.
Hello! The Ford Performance 3.73 Gears and Install Kit will have everything necessary for your 2010 GT.
Yes, this kit definitely has everything needed to upgrade those gears to 3.73, aside from a new tune. You will need a new tune to adjust your speedometer and, if you have an automatic, your shift points.
a 3.55 gear ratio tends to be better in terms of fuel economy as the engines RPM would be lower than a 3.73 gear ratio at the same speed.
This will weigh around 30 lbs.
The 3.73s may be a bit extreme for the V6 models, but you should be fine with daily driver. I would recommend not going with anything above the 3.73s.
We do recommend a tune when upgrading the gears.
Unfortunately we do not currently offer customer installs at this time. I would recommend checking with a Ford dealership as they should be able to do the install without any issues.
(approx) 4 Hours
Mechanical expertise or professional installation required.
What's in the Box
Does not fit 2013 Boss or 2013-2014 Shelby GT500 Mustangs with axle codes S-215-D and S-219-D.