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Ford Performance Speedometer Recalibration Tool (94-10 All)

Item 50139
AmericanMuscle no longer carries the Ford Performance Speedometer Recalibration Tool (94-10 All). Please check out 1999-2004 Mustang Gears for an updated selection.
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Features, Video & Details

  • Corrects Speedometer for Tire Size Changes
  • Corrects Speedometer for Rear Gear Changes
  • No Reprogramming of PCM Necessary
  • Easy 4 Wire Installation
  • Fits 1994-2010 Mustangs

Review & Installation Video

Review & Install Video

Corrects Speedometer. Is your Pony's speedometer off because you changed your rear gear ratio or tire size? Then you will need a Ford Racing Speedometer Recalibration Tool to correct your speedometer.

No Reprogramming Needed. The Ford Racing Speedometer Recalibration Tool scales a frequency based on the vehicle speed signal up/down to maintain accurate speed indication to the speedometer and to the PCM with no reprogramming of PCM necessary.

Application. This Ford Racing Speedometer Recalibration Tool will work on the 1994-2004 automatic and manual Mustangs as well as 2005-2010 manual Mustangs. 2005-2010 automatic Mustangs are limited to the equivalent of one step higher or lower gear change ratio (< /- 10% change).

Fitment: Details

CA Residents: WARNING: Cancer and Reproductive Harm -

What's in the Box
  • (1) Speedometer Recalibration Tool
Installation Info
Tech Specs
Will it fit my Mustang?
  • Bullitt - 01, 08, 09
  • Cobra - 94, 95, 96, 97, 98, 99, 01, 03, 04
  • Cobra R - 95, 00
  • GT - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10
  • GT500 - 07, 08, 09, 10
  • Mach 1 - 03, 04
  • V6 - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10

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      Questions & Answers (17)

      5 Top Rated Questions

      Do I need this if I already have an SCT Tuner? The BAMA tune form has a section for tire size and gear ratio, so my question is leaning towards: Is it really necessary for me to purchase such an item when I can get a free BAMA tune for my upgraded 4.10 gears? It just doesn't make sense to purchase the re-calibration tool if a customer already has a Tuner... if that's the case then it should be in the product description so that people aren't mislead.

      • That is correct. If you already have a tuner, you can just get an updated tune to account for the change in gear ratio. No need to purchase this as well; you just need one or the other.

      Helpful (11) Show 1 more answer

      Will this work on 94 gt with 4.10 gears swap

      • The tool is compatible with your 94 GT with 4.10 gears.

      Helpful (0)

      2005 mustang gt going from 3.55 to 4.10 gears, video stated I will lose cruise control would this be to much of a drastic change for the ford performance calibration tool thanks

      • that is more than a 10% change.That is 2 steps up. You would have to go with 3.75 gears to use the tool still. 

      Helpful (0)

      I have a 1995 mustang gt, I made a swap with a t56 6 speed 03 cobra, but when I plug the sensor the speedo reach 120 mph only in first gear, in second gear it goes all the way. what I know 94-98 have mechanical speedo, and the T56 has electronic speedo. will this fix my issue?

      • The correct fix for this will depend on which version of the T56 you are using, however the Ford Performance Speedometer Recalibration Tool will typically not be able to correct for this as the speedometer is mechanical/cable driven.

      Helpful (0)

      I have a 1994 Thunderbird with the 4r70w will this work with it?

      • We have not tested the Ford Performance Speedometer Recalibration Tool with vehicles other than Mustangs.

      Helpful (0)
      Post Your Question
      10 More Questions
      If i put 4.10 gears in my 06 mustang then in a couple weeks put frag radials on will I have to reinstall this or will this work for multiple times or would I be better off buying the Bama Tuner? 1 answer
      Will this work on a auto to manual swap?? I have a 1997 Gt with now a 2002 t45 trans. My speedometer just goes all the way max. Note: I’m still running on an auto ecu. Would I have to take off the automatic functions off first and then do the recalibration or I can do recalibration first and then turn off the auto functions. 1 answer
      I have a 1998 lincoln mark viii with 4.6 32v and a 4r70w trans. Putting in 4.10 gears, i am told I need a tune or it will not have the proper shift points. Could this device work for me? 1 answer
      After the transmission swap in my Cobra the speedometer is almost 120mph off. If I go around 25 the needle goes past 160. Could this tool potentially fix an error that large? 1 answer
      I have a 1999 GT 5-speed that the speedometer is not getting the signal through the computer because the previous owner replaced the '99 T45 with a '97 T45. Will this Speed Calibration Tool allow my older VSS style transmission communicate with my newer OSS style computer/speedometer? 1 answer
      OK, so if you have an 05-9 V6 with auto trans and upgrade to a 3:73 rear you have to buy a tuner to recalibrate the speedo? 1 answer
      Why are people having problems with this on auto transmissions , fixing to order 410 gear set and recalibration tool but don't wont problem. 1 answer
      on my 01 gt i have 3.73 gears,the speedometer is only 5mph slow, but the odometer is fast,it is adding 1 tenth mile more for every mile i travel,will this recalibration tool fix my odometer? 2 answers
      would this work on a transmission swap? I have a 3.8 98 ford mustang, 5 speed. The transmission in it is a late model The 99-04 V6 T5; 1352-260 tag number. when I plug the wire into the speedo plug, it reads way beyond the normal speed for each gear. will this speed cal fix my problem? 1 answer
      Can this be used to recalibrate for a 160MPH speedo overlay? 1 answer

        Customer Reviews (61) Write a Review

        Ratings Summary

        4.3 out of 5 overall rating from 61 customers

        Installation Time: Afternoon

        Installation Cost: $100-$250

        • March 24, 2019

          4 1998 GT - PaulS Installation Time: Less than 1 Hour

          Speed Cal

          Easy install and really works. No complaints. Had to

          Helpful (0)
        • January 10, 2019

          5 1996 V6 - Titiania Installation Time: Less than 1 Hour

          Works great

          Really had to adjust it a few times to calculate everything right. But Once you got it dialed in right. It works like a charm.

          Helpful (2)
        • December 09, 2018

          5 2003 Mach 1 - NathanW Installation Time: Afternoon

          '03 Mach One

          Wring banks will be different for Mach 1 from the instructions for 99/01 Cobra if you use the under the hood route. Just find and use the green/white wire and all will work out well.

          Helpful (2)
        • July 09, 2018

          5 1996 GT - ChrisK Installation Time: Afternoon

          Highly Recommend

          1996 Mustang GT with 373 gear swapped from T45 with VSS to 3650 with OSS. Set this recalibrator to 0,2,4 and the speedo is very close when compared with a GPS speedometer. The instructions are very good and I recommend splicing into the harness in the engine bay. Highly recommend.

          Helpful (6)
        • May 15, 2018

          5 1998 GT - JohnS Installation Time: Less than 1 Hour


          Hard to soder in because the factory wire harness is short, but works great

          Helpful (6)
        • May 12, 2018

          4 1996 GT - JeffB Installation Time: Afternoon

          Working after transmission swap to a 3650

          I removed my t45 and switched to a t3650 tremec. The only downside was the lack of instuctions for the setting it up when going from vss to oss. I just got it reading close to being correct after setting ihe dials to 0 2 4.

          Helpful (9)
        • April 16, 2018

          5 2004 Mach 1 - GaryD Installation Time: Shop Install Installation Cost: $250-$500

          Recalibration Tool Worked!

          Installed the recalibration tool on my 2004 Mach I to fix the speedometer with the 4.10 gear and tire changes. Tool was easy to calibrate and the speedometer works perfectly.

          Helpful (6)
        • March 26, 2018

          4 2007 GT - WilliamP Installation Time: Less than 1 Hour

          Does the job spend the extra and get a tuner.

          Worked well for calibrating the speedo. Easy install. Those who are wanting to installed 4.10 gears in a 2007 mustang beware that if you install this you will lose your cruise control. Also even with traction controls off engine will pull power when under heavy throttle to keep traction. Going from 3.35 to 3.73 is to big of a jump in gear ratio. The PCM will detect the difference and that is why you lose cruise control. If you are only going up one set of gears let say from 3.35 to 3.55 this will work great. Just can’t jump up from 3.35 to 3.73. Save yourself some time and buy a tuner.

          Helpful (6)
        • March 07, 2018

          5 1997 Cobra - TravisM Installation Time: Less than 1 Hour

          Very skeptical

          I was very skeptical about how this thing worked but it was super simple to hookup and worked great have had it on now for a few months with no problems

          Helpful (7)
        • November 09, 2017

          5 2003 GT - RandyM Installation Time: Less than 1 Hour

          Quick, straight-forward install.

          I discovered that the 2003 GT Convertible I recently purchased had a rear gear swap from 3.27 to 3.73 based on the speedo indicating ~10 mph higher than actual speed at 60 mph (88 adjustment from stock required). I knew it was way off so checked it with a portable GPS. Install was well directed and easy to understand. Set recal. tool at 88 and matched GPS speed indication.

          Helpful (8)
        • September 03, 2017

          4 1994 Cobra - ThomasS Installation Time: Afternoon

          Very nice. Have to tinker with it.

          The box installs easy enough on the sn95, my only issue was I didnt install my rear end nor do I know what is in it entirely. There is an option to use mile markers and your odometer to calibrate the box, which is great if your sn95 is magic and the odometer works. I ended up starting adjusting the smallest frequency knob until my Speedo was in the ballpark range and then using a gps app to know my exact speed. I kept adjusting the knobs higher until I reached the correct speed. This involves a lot of driving and stopping and adjusting. Took me about 30-45 minutes to calibrate. But I'm dead on now and don't need an extra Gage in the car to know my speed.

          Helpful (10)
        • June 09, 2017

          5 2005 GT - GeorgeK Installation Time: Less than 1 Hour

          WORKS GREAT!

          Installs easy and works great ! just follow the formula for determining amount of error of speedometer reading and dial in on correction tool .

          Helpful (8)
        • May 30, 2017

          5 2003 V6 - William Installation Time: Less than 1 Hour

          Easy to install

          Very easy to install under the hood. took me about 30 min. to install

          Helpful (8)
        • April 25, 2017

          5 1996 GT - JeremyS Installation Time: Less than 1 Hour

          Does what was needed

          Very easy install. Took maybe 10 minutes wiring and calibrating. Calibration was a little different but I figured it out with no problems. Speedo is now right on.

          Helpful (7)
        • March 03, 2017

          5 2002 GT - PYNE Installation Time: Afternoon

          Gear Change 3.22 to 3.73

          Instructions were good, except the part about switchs being all at 0, and speedo should read 45 MPH, only read 25 MPH, but still corrected the speedo 14 that I needed.

          Helpful (7)
        • February 22, 2017

          5 1997 GT - DavidB Installation Time: Less than 1 Hour

          Works as it should

          Straight forward instructions no problems really does work!

          Helpful (7)
        • November 06, 2016

          5 1997 GT - Mango Installation Time: Less than 1 Hour

          Well worth the money!

          I bought this to correct for a 3.27 to 4.10 gear swap in a 97 GT. I isntalled it under the hood as opposed to down by the transmission which made the installation much easier. After getting it hooked up, I did the math and set the box accordingly. A quick drive showed that i was close but still 5 mph off. I adjusted a couple more times and its dead on right now.

          Helpful (8)
        • September 12, 2016

          5 1998 GT - S6ul6fd6ath

          Works Perfect

          My first item was defective but american muscle rushed to get me my replacment. Hooked up the second unit and everything is now 100 spot on. I had to call american muscle for some help with the dials but they helped me solve everything thanks american muscle.

          Helpful (7)
        • September 02, 2016

          5 2001 GT - guzzi1k

          Speedo recalibrator

          Easy to install, does what it's supposed to do. 3.27 to 3.73 gears, speedo now reads correctly.

          Helpful (10)
        • August 16, 2016

          5 1998 Cobra - StevenMayfield

          Recalibration works

          Installed the recalibration tool on my 98 with 4.10s and t56 swap. Installed it in the engine bay super simple only 20mins. The mathematics they said do didn't work. I'ma go with because of the t56 so I whipped out the gps speedo and drove around dialing it in. Works great must have!!!!!

          Helpful (7)

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