Speedometer not workin correctly, My speedometer measures like 20 mph faster than I'm driving Options

[celicabob]

Hey everyone. Im basically a newb when it comes to cars and I am hoping someone can help me out. I've got a 94 Gt auto and I think that the trannie may have been replaced,but I'm not sure. Anyways my speedometer is way off. I will be doing like 45 and it says I'm going 90 also some days it seems to be off by only about 10 or so mph. It seems to be more inaccurate on rainy days, but even on dry days it is slightly off. Can ayone tell me what is wrong and how it can be fixed. Any help will be appreciated.

[celicabob]

If I switched speedometers from a junyard one that would only show the mileage on the junyard speedometer and not the original mileage on my car, right? I would like to avoid this. Is there any other way to fix this problem?

[garin]

yeah, i'm not sure how you can roll back the odometer. if you are up to it take the needle off and play around with it till it is calibrated properly. be careful not to break it though. i had to take my needles off when i put in glo gauges (i ended up taking my glo gauges out because they kept on burning out. never buy glo gauges, just do LED's). i took off the needle and turn on the car. placed the needle at 0 mph when it was at idle. i'm not sure if this will work, but try it if you feel confident. good luck. hope this helps.