2004 mustang gt mileage added or subtracted from odometer w/gear change

[BILL JACOBS]

My 2004 Mustang GT originally had a 3:27 gear, but previous owner installed a 3:73 gear setup! Using the speedo readings without flashing computer what is the odometer mileage doing, adding mileage or subtracting!? I previously installed the Ford re-callibration box, it changed the speedo to correct reading, but now the torque converter is kicking in and out at random! talked to local Ford dealer and tranny tec and said they didn't know what to do other than playing around with box! If I adjust box, then the speedo will be off, so I just removed it and am living with wrong speedo readings! Anyone got any Ideas?
Thanx Bill

 

[Sluggie24]

With that gear difference the odometer is recording more miles than you actually drive. It's my understanding that the best way to recalibrate the speedo is with a handheld tuner.

 

[BILL JACOBS]

Hi Sluggie24: Thanx for the info, but where do u get the hand held tuner that I don't have to pay an arm and leg to buy? I already paid 100 for the Ford re-calibration unit! Can the Ford dealer flash the computer? They say they can, but it's another 100 just to try, plus more if they have to fine tune!!
Bill

 

[BILL JACOBS]

OK, I found the info on the tuner u gave me earlier!
Thanx: BILL