Can I use ForScan to recalibrate my speedometer after gear change

[BrandonStang]

Hello, I have 2011 GT that I purchased recently and I realized the speedometer was reading higher that the GPS on my phone. After checking I found that my rear axle gears have been changed from the stock 3.31 (sticker is still on the axle) to a 3.73.

I recently downloaded ForScan and I wanted to know if anyone knows a way to adjust for the gear difference so that the speedo is correct. The version I have does not have the tire changer option in the menu on ForScan like I have seen for the F-150 or newer Mustangs

 

[Berlioz101]

I have been told that FORSCAN cannot change the gear ratio to have it affect your speedometer. I've asked in three different places but they all have said to get an SCT tuner to affect this. Unfortunately that's really all I know, I'm having the same issue, except I went from a 3.15 to a 3.31.

 

[86GT351]

No you can not

 

[desertcoyote]

for 2014 you can but you're limited to up to 3.73 and a set of tire sizes.

but obd link device and connect it to a windows laptop. turn ignition. connect to your car following forscan instructions. then it will identify your car. then there is a section where you edit some configuration. from there you can change gear ratio and tire size.

 

[Juice]

Yes you can, on an untuned pcm. If you are tuned, it depends on how the tune is set. There is a switch to use gear/tire info from the tune OR VID block. Yes, there is a range limit (3.15-3.73)

I got tired of flashing the pcm just to correct the speedo. I use Forscan for that now. Its way faster than a reflash, and no chance of bricking the pcm. If your tume is set to not use the VID block, than Forscan cannot change the gear ratio. You need to update the tune first.

**Works on 13/14.