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USA Standard 3.90 Gears (05-09 GT)

AmericanMuscle no longer carries the USA Standard 3.90 Gears (05-09 GT). Please check out 2005-2009 Mustang Gears for an updated selection.
2 Reviews
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$149.99

  • Item #21615G05
  • Market Price $169.99
  • You Save 12% ($20.00)
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AmericanMuscle no longer carries the USA Standard 3.90 Gears (05-09 GT). Please check out 2005-2009 Mustang Gears for an updated selection.

Features
  • USA Standard Gear
  • Manufactured from 8620 gear steel
  • 3.90 gear ratio
  • 8.8" ring gear diameter
  • Fits 2005-2009 GT, Bullitt, and Shelby GT500 Mustangs
Description
Wake Up Your Pony. Installing a set of steeper gears is a great way to get your Mustang into the power band quicker for improved low end torque and faster acceleration off the line. A set of USA Standard Gears will really wake up your Pony. Better Than OEM Quality. Using state-of-of-the-art equipment and manufacturing techniques USA Standard Ring & Pinion sets are made to higher than OEM standards from high grade 8620 gear steel and are backed by a one year warranty.

Recommended Upgrade. Changing the rear axle gear ratio will throw off the calibration of your Mustangs speedometer, but a Ford Racing Speedometer Recalibration Tool is an inexpensive way to fix this issue.

Application. This USA Standard Gear 3.90 Ring and Pinion Gear set will fit all 2005 to 2010 V8 Mustangs including the GT, Bullitt and GT500 models. A master bearing kit is recommended by most installers, especially on high mileage vehicles, see drop down option above.

Attention 2010 and newer Mustang Owners. Starting in 2010 Ford changed the inner rear gear pinion bearing in all 8.8" equipped Mustangs. Because of this you will require a new 8.8" rear gear pinion bearing (Ford part# 9L3Z-4630-A) for proper installation, please 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.

Mustang Fitment: 2005 2006 2007 2008 2009 Details

What's in the Box
  • (1) Ring gear
  • (1) Pinion gear
Installation Info
Tech Specs

Approximate RPM for 2005-2010 GT


Manual
Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
1 4065 5691        
2 2405 3368 4330 5292 6254  
3 1588 2223 2858 3493 4128 4763
4 1203 1684 2165 2646 3127 3608
5 818 1145 1472 1799 2126 2453


Automatic
Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
1 3873 5422 6971      
2 2754 3856 4957 6059    
3 1852 2593 3334 4075 4816 5556
4 1203 1684 2165 2646 3127 3608
5 854 1195 1537 1879 2220 2562
Fitment
  • Bullitt - 08, 09
  • GT - 05, 06, 07, 08, 09
  • GT500 - 07, 08, 09

Most Helpful Reviews View All

Overall Rating 4.5/5 Write a Review
5/5
Gears and Tuners and Tires oh my...

There is NOTHING short of a forced induction implant that makes as much performance impact on your stang. If you want to get up and get going and stay going Gears are the answer. The tuner was nice, but

Read More
Helpful (1) (0)

4/5
great

Im a daily driver and most of my driving is done on the interstate. I was afraid of 4.10 because im always doing 80. So i took the the gamble on this gear not only for the price but also because frpp does

Read More
Helpful (0) (0)

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Reviews (2) Write a Review

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4.5

out of 5 stars

2 Customers Recommend this Product

Installation Time:Weekend

Installation Cost:$250-$500

  • Performance Gain: 5 5/5
  • Fit: 5 5/5
  • Bang For Your Buck: 5 5/5
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  • 5/5

    Gears and Tuners and Tires oh my...

    July 27, 2012

    There is NOTHING short of a forced induction implant that makes as much performance impact on your stang. If you want to get up and get going and stay going Gears are the answer. The tuner was nice, but it wasn't until the gears were installed that I really felt a performance gain. don't think about it, just do it, because it's so worth it.

    McCrank

    Year: 2007 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 5 Colorado Springs, CO, USA

    Helpful (1) (0)

  • 4/5

    great

    March 22, 2013

    Im a daily driver and most of my driving is done on the interstate. I was afraid of 4.10 because im always doing 80. So i took the the gamble on this gear not only for the price but also because frpp does not sell 3.90. There is a small whine when im between 40 and 50 but other then that its quite. My suggestion is if your doing alot of high speed cruising then go 3.73. My rpm at 80mph sits about 2650 maybe 2700.

    cookie117

    Year: 2007 Model: GT Driving Style: Daily Driver

    Helpful (0) (0)

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