Free Shipping On Orders Over $49. Details

Talk to a Mustang Enthusiast
M-F 8:30A-11P, Sat-Sun 8:30A-9P
Win $5,000 For Your Mustang! Enter Daily

EXCEL from Richmond Ring Gear and Pinion Kit - 3.90 Gears (99-04 GT)

Item 21527G99
Market Price $186.39 You Save 12% ($21.44)
Our Price


FREE Shipping

Will this fit your Vehicle?

Change Vehicle Help?
Update or Change Vehicle
In Stock Ships same business day.
Ship to: Ashburn - 20149
Sorry, please enter a valid US or CA postal code
We're sorry, zip can't be updated at this time.
    Create a list
    Add to New List

    Saved - View your saved items

    We're sorry. We couldn't save this product at this time.

    Features & Details

    • Superior Quality
    • 3.90:1 Gear Ratio
    • 8.8" Ring Gear Diameter
    • For Street or Track Use
    • Made in the USA
    • Fits 1999-2004 GT, Bullitt, Mach 1 and Cobra Mustangs
    Improve Off The Line Acceleration. Is your V8 powered New Edge Pony sluggish off the line? If the answer is yes, it's because of the lower ratio gear and pinion set installed by Ford at the factory. Most 1999-2004 Mustangs came standard with 3.27 gears, which are great for daily commuters who are looking for good fuel economy, but not for the hardcore performance enthusiast who wants rabbit quick acceleration. By upgrading to a set of higher ratio 3.90 Richmond Excel Gears your Mustang will enter its power band sooner which will help improve low end torque and give you the quick off the line acceleration you're craving.

    Superior Quality. Richmond proudly manufactures their Ring and Pinion Gear Sets right here in the USA. Using state-of-the-art manufacturing processes and extensive quality control testing, Richmond produces a superior quality Ring and Pinion Gear Set at an excellent price. Richmond is so confident in the quality of their products that they back them with a 6 month, 50,000 mile no-nonsense warranty.

    Recommended Upgrade. Please note that when changing the gear ratio of your Mustangs rear differential that the calibration of your speedometer will no longer be correct and will display the wrong speed. However, you can easily fix this annoying issue with a Ford Racing Speedometer Recalibration Tool (sold separately).

    Application. This 3.90 ratio Richmond Excel Ring and Pinion Gear set will fit all 1999 to 2004 V8 Mustangs equipped with an 8.8" rear end, including the GT, Bullitt, Mach 1 and SVT Cobra models. 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.

    Fitment: 1999 2000 2001 2002 2003 2004 Details

    MPN# F88389

    CA Residents: WARNING: Cancer and Reproductive Harm -

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

    Approximate RPM for 1999-2004 GT

    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

    Gear @25 MPH @35 MPH @45 MPH @55 MPH @65 MPH @75 MPH
    1 3416 4782 6148      
    2 1864 2610 3355 4101 4847 5592
    3 1203 1684 2165 2646 3127 3608
    4 842 1179 1515 1852 2189 2526
    Will it fit my Mustang?

      Customer Photos

        Q & A

        No questions about this product yet.

        Ask the First Question

          Customer Reviews (3) Write a Review

          Overall Rating 2.7

          out of 5 stars

          • 4/5

            October 18, 2010

            RICHMOND 3.90 GEARS


            BRYAN ISBELL

            Year: 2003 Submodel: Mach 1

            Helpful (5)

          • 3/5

            October 14, 2010

            Richmond Gears 3.90

            The 3.90 gears really improve your acceleration and are the cheapest way to go faster without sacrificing too much fuel mileage/drivability. I was impressed by the quickness in which my order was received to my front door. However, after installing my 3.90 gears (making sure that both the pinion depth and backlash were correct) I noticed a whine. The whine did not subside after the break in period. I contacted AM who was very helpful and was instructed to speak with Richmond. Richmond did not really do anything to help me and hopefully the gears hold up. So far noise is the only problem. If I could do it again I would purchase Ford Racing gears.

            Bill Henry

            Helpful (10)

          • 1/5

            January 09, 2010


            Good ratio...VERY NOISY at cruise...and yes it is set up right ..pattern was perfect......replacing with FORD Gears....also Motive Kit for 8.8 did not include any small shims....only 14's and 30's.

            chris s

            Helpful (10)

          Related Mustang Categories