Talk to a Mustang Expert
1-888-332-7930
M-F 9-9,Sat 9-5:30,Sun 12-4 ET

Free Shipping on Everything. Seriously. Details

Motive Performance Plus 3.90 Gears (99-04 GT)

9 Reviews
Clearance Price

$183.99

  • Item #21102G99
  • MPN# F888390

  • Market Price $271.19
  • You Save 32% ($87.20)
In Stock Ships same business day. Choose options to add to cart
Free Shipping on Everything
Customer Photos
Features
  • Superior quality
  • CNC-cut from 8620 gear steel
  • 3.90 Gear Ratio
  • 8.8" Ring Gear Diameter
  • For street or track use
  • Fits 1999-2004 GT, Bullitt, Mach 1 and Cobra Mustangs
Description
Improve Overall Performance. A set of Motive Performance gears will wake up your Pony and get it moving faster off the line. Steeper gears are a great way to lower quarter mile times and improve responsiveness without sacrificing driveability. 3.90 gears are perfect for the Pony that needs more than 3.73s but less than 4.10s, offering a great blend of performance and efficiency.

Superior Construction & Precision Fit. These Motive ring and pinon gears are CNC cut from high grade 8620 gear steel, and factory lapped for precision fit. Each set is hardness tested prior to leaving the factory to ensure the highest quality. Unlike other brands, Motive Gears do not have a reputation for "gear whine".

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 Motive Performance Plus 3.90 Ring and Pinion Gear set will fit all 1999 to 2004 V8 Mustangs including the GT, Bullitt, Mach 1 and 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

Won't fit? Add an exception

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

Approximate RPM for 1999-2004 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 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?
  • Bullitt - 01
  • Mach 1 - 03, 04
  • Cobra - 99, 01, 03, 04
  • GT - 99, 00, 01, 02, 03, 04

Most Helpful Reviews

5/5
Excellent Ring and Pinion!

I recommend these Motive 3.90 gears to anyone considering between 3.73 or 4.10 gears, this ratio is perfect for the T-3650 5 speed and even the T-56 6 speed manual transmission. Motive makes an excellent ...

Read More
Helpful (3)

5/5
better than 4.10s imo

Went from stock to 4.10s. that lasted about a year. Decided to go down to 3.90s. They are definatly a much more street friendly gear, but still get up and move! 3rd redlines at about 85, and 4th is ...

Read More
Helpful (3)

Read All 9 Reviews
Overall Rating 4.4 out of 5 stars

Customer Photos (1) View All Photos

You Might Also Like

Q & A

No questions about this product yet.

Ask the First Question

More Products You Might Like

Customer Reviews (9) Write a Review

Overall Rating 4.4

out of 5 stars

Installation Time:Shop Install

Installation Cost:$100-$250

  • Performance Gain 5 5
  • Fit 4.333333 4.3
  • Bang For Your Buck 4.666667 4.7



  • 5/5

    Installation Time: Weekend

    January 27, 2012

    Excellent Ring and Pinion!

    I recommend these Motive 3.90 gears to anyone considering between 3.73 or 4.10 gears, this ratio is perfect for the T-3650 5 speed and even the T-56 6 speed manual transmission. Motive makes an excellent ring and pinion. I swapped out my old Motive 3.73 for these 3.90, Motive gears are made with great precision. The ring run-out was perfect and pinion depth (calculation) was spot on to the marking on the pinion head itself. Also, I would advise a bearing and shim installation kit towards your build, it's always "good insurance".

    MavLS7

    Year: 2003 Model: Mach 1 Driving Style: Street / Strip 'Stangs I have owned: 3 New York, NY

    Helpful (3) (0)

  • 5/5

    September 10, 2009

    better than 4.10s imo

    Went from stock to 4.10s. that lasted about a year. Decided to go down to 3.90s. They are definatly a much more street friendly gear, but still get up and move! 3rd redlines at about 85, and 4th is around 115, so you'll definatly still have plenty of oomph to blow past the slow traffic on the freeway-

    Brian

    Helpful (3) (0)

  • 5/5

    June 02, 2010

    perfect gear

    great gear not to low like 410s but still feels better then 373s.. i had gotten a rebuild kit with the gears.. i have not had any whine unless in reverse..

    chalmers

    Helpful (2) (0)

  • 5/5

    March 07, 2010

    crazy..

    The only word to describe these gears is crazy! They gave my '02 GT so much more life. I had a hard time deciding between 373s and 410s, so i just went with these and i am glad i did!

    Kevin

    Year: 2002 Model: GT

    Helpful (2) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    July 14, 2013

    Woke up my 4.6 more than any other upgrade

    This was a great investment. Went from stock 3.27's to these. My 99 cobra has never had so much useable power. I hit about 2700 rpm at 75mph with a T-45 tranny in 5th so it's still completely highway capable. This also helped minimize the cam lope I had while in gear at lower rpms. I will be needing new tires now though. Over all a great buy. One note is the shop I used didn't have the right size shims so it took a few days for install. Also u will need to adjust your tune to the new ratio or your speed-O will be off by quite a bit.

    Niixx

    Year: 1999 Model: Cobra Driving Style: Daily Driver 'Stangs I have owned: 3 Kansas City, KS, USA

    Helpful (1) (0)

  • 4/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    July 09, 2013

    Excellent choice for a 99-01 Cobra

    I chose these gears for my 99 cobra and took them immediately on a 4300 mile road trip after the break in time. I felt that the 3k rpms at 85 was reasonable for the trip and I didn't notice much of a gas millage drop after the install. Performance wise these we killer for the bends and helped out my top end on my stang. I topped out at 172 on the autobahn (gps verified) with the aid of these gears where I wasn't able to get over 160 with the previous gears (long tubes also were added between runs). These gears made me want a t56 for my car because it feels like I have no overdrive now, 5th is VERY usable and the car still pulls like a train! The only thing I wasn't happy with is the price premium over the 3.73's/4.10's its a bit of a kick in the teeth by Motive. Very nice gear and minimal whine; I have aluminum bushings in the rear so I expected more.

    Top 100 Contributor

    RedSnake

    Year: 1999 Model: Cobra Driving Style: Daily Driver 'Stangs I have owned: 4 Cambridge, UK

    Helpful (1) (0)

  • 5/5

    October 09, 2007

    Great get up and go.

    I feel that these are the great in between gears to have. I didn\'t want 3.73\\\'s but I didn\'t want 4.10\\\'s either. You will get a great improvement when you hit the throttle.

    Travis

    Helpful (1) (0)

  • 3/5

    December 05, 2009

    whine

    good compromise from 4.10s but have a tendency to whine.

    david

    Helpful (0) (2)

  • 3/5

    July 14, 2010

    390

    Had gear professionally installed, greater acceleration and higher rpms, unfortunately the gear whines, would recommend ford racing, but they dont make a 390 so i chose motive because i wanted a 390, ill live w it

    Matt

    Helpful (0) (3)

Related Categories