My Speedometer is of by about 7 mph when driving around 60. I varies with speed, increasingly off the faster I'm going. My mechanic said that that meant that there was probably something not right in the transmission. This concerns m because I just had my transmission rebuilt and I want to make sure everything is okay with it before the 1 yr warranty is over. However the speedo was already off before my transmission was rebuilt. So mainly I just want to make sure that my transmission is ok. If its gonna break it better break now.
Thanks for your help.

94 Honda Accord LX
218,000 mi