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Ford Performance 3.73 Gears and Install Kit (86-09 V8 Mustang)

Item 100576
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$288.23 (kit)

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      Video Review & Installation

      If you're looking to improve the acceleration and off-the-line performance of your Mustang, stepping up to a numerically higher gear ratio is a great way to do so. Now the Ford Performance 3.73 gear set and install kit will be from one of the most trusted names in parts for your '86 to '09 V8 Mustang, with the 8.8 solid rear axle. Now this kit will include a brand-new ring and pinion as you guys can see, along with everything you need to get them in place.Price point for the 5-star rated kit will be in the mid to high $200 range, and the install will not be for the timid or inexperienced mechanics out there so let's call this one a full-blown 3 out of 3 wrenches on the difficulty meter with a little bit more detail on that later in the video. So it's no secret that most of the factory gear ratios for the earlier cars like the Fox Bodies, and the SN95s, and even some of the early S197s weren't exactly ideal for off-the-line performance and acceleration. In fact, it was quite the opposite.Now most of these earlier cars were working with either a 2.73, a 3.08, or in some cases a 3.27 gear until some of the early S197s ushered in an optional 3.55 ratio. And with all that said, again, a great way to increase your off-the-line performance and acceleration without even adding horsepower is to install a numerically higher gear ratio or a shorter gear as they're sometimes referred to as.Now doing so will help you get through those gears a little bit faster and get you up to speed quicker. But the only drawback being a slight hit to your fuel economy, depending on how aggressive you go. But, with the days of overdrive manual and automatic transmissions, it's not nearly as bad as it used to be back on the old four-speed cars.But getting into the kit that we have here and with that fuel economy thing in mind, I would argue a lot of people would probably prefer the 3.73 to a more aggressive 4.10 or higher gear ratio, because, depending on your factory ratio, you are still getting a much shorter gear with the 3.73, especially if you had a 2.73 car or even a 3.07 car. So, the car basically is going to feel totally different but without turning more RPM while cruising on a highway like you would with a 4.10 or something higher. Basically, it's gonna be a great compromise. Now as far as your physical construction of the gears are concerned, well, really nice stuff here from Ford Performance, and that is what we've come to expect from anything with the blue oval on it. We're gonna be looking at the strong forge construction throughout, CNC cut, of course, along with the lapped teeth all finished in that black oxide coating.Now the gears had been made in the USA, and Ford Performance likes to tout that these are gonna be some of the quietest gears you'll find available in the after-market. But on the subject of noise, it is important to point out, for me, that a lot of times the noise might not be coming from the gears themselves but rather the install or the setup of the gear or rather the ring and pinion, which does lead us into the next part of our product here. And that is the installation kit. And while I don't have every single part on the table with me for this video, you will be receiving everything you need to get the new ring and pinion installed and set up in your V8, and that does include brand new bearings, new seals, new shims, crush sleeves, pinion nut, gear marking compound and brush to check the pattern in-depth, your diff cover gasket, and even a couple of quarts of the 75-90 Royal Purple gear oil in addition to the 4 ounces or 3.8 ounces of the required friction modifier.So a very complete kit is what I'm trying to say here, guys, at the end of the day, and one that will be beneficial to either you or your mechanic when it comes time to get everything installed. And speaking of the installation, listen, getting gear set up properly can be a bit of an art form and does involve a bare amount of work under the car in addition to using some specialty tools like the press, the dial indicator, and things like that.So because of this, we're gonna call it a full three out of three wrenches on the difficulty meter. Those of you who have done this in the past knows what's involved, so, yeah, no problem locking this out and you're definitely gonna save yourself some money when it comes to labor. On the other hand, for the novice mechanics out there who really aren't too familiar with this sort of thing, you might wanna get this one installed by your local shop. It's not a fun day in the garage. And again if you don't have access to all the specialty tools, it can lead to a noisy operation. Typically labor for a job like this will vary depending on your area, of course, but I'd say a ballpark of 500 bucks, give or take, is what you can expect for the labor here. But again if you've done this before and you know what to expect. On the other hand, I would strongly recommend getting this one knocked out by your local shop.Another big thing to keep in mind when making the change to a different gear ratio is the change or effect that this will have on your speedometer, and it will need to be corrected. Now you have a couple of different options, '79 to '98 cars or V8 owners out there, you can simply replace your speedometer gear. It's gonna be the most cost-effective way to go about doing so. '99 and newer cars, on the other hand, with that VSS sensor, you can either fix this through a handheld device or tuner, or you can look into a speedo recalibration box from a company like Ford Racing, for instance, on the site here for a couple of hundred bucks. But in closing, guys, if you're looking to really kick up that off-the-line grunt of your V8-power Mustang, improve your acceleration and your ETs, a set of 3.73s from Ford Performance would be a great choice, and you can grab yours right here at

      Product Information

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

      Features & Specs

      • Money Saving Combo Kit
      • Ford Racing 3.73 Gears - 8.8"
      • Motive 8.8" Rear End Installation and Bearing Kit
      • 1 Bottle of Ford Racing Friction Modifier
      • 2 Quarts of Royal Purple Max Gear 75w90 Gear Oil
      • Fits 1986-2009 V8 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, 1 bottle of Friction Modifier, 2 bottles of 75w90 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 Speedometer Gear, 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 1986-2009 GT, Bullitt, Mach 1, Shelby GT500 and 1994-1998 SVT Cobra. It will not fit the 1999-2004 IRS equipped Cobra Mustangs.

      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.



      Ford Performance 100576

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Ring gear
      • (1) Pinion gear
      • (1) 3.8 fluid oz bottle of Friction Modifier
      • (2) one quart bottle of Royal Purple Max Gear 75w90 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

      Customer Reviews (269)

        Questions & Answers

        10 More Questions

        Will It Fit My Mustang

        • Bullitt - 01, 08, 09
        • Cobra - 93, 94, 95, 96, 97, 98
        • Cobra R - 93, 95
        • GT - 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09
        • GT500 - 07, 08, 09
        • LX - 87, 88, 89, 90, 91, 92, 93
        • Mach 1 - 03, 04
        • Other - 86

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