Question?? If you change your rear axle gears from the stock ratio to 3:73-1 how do you get the speedo back to read correctly?? I had the PCM redone but it seems I am still off by 10km/h up to 100 then 20 off over 105km/h. Running down the road if the speedo says 60 I'm only doing 50 and if I'm doing 120 it reads 140 km/h. I know in older cars we used to change the gear in the tranny, is that done this time as well?? Take care Mustangnut

Question?? If you change your rear axle gears from the stock ratio to 3:73-1 how do you get the speedo back to read correctly?? I had the PCM redone but it seems I am still off by 10km/h up to 100 then 20 off over 105km/h. Running down the road if the speedo says 60 I'm only doing 50 and if I'm doing 120 it reads 140 km/h. I know in older cars we used to change the gear in the tranny, is that done this time as well?? Take care Mustangnut

I see you said you had the PCM redone but it's done by the program.Do you have a handheld programmer like SCT or Diablo?If you had it done at a speed shop they should have done it before they gave it back to you.:confused:

07 I called the guy who did my calibration and he said he thinks it MAY not have worked but he couldn't get to his program as his computor is down, so he told me to call him next week and he will let me know and we will go from there. Thanks Mustangnut