I don't think there is any difference in the speedo in dash. The gear for speedo in the trans makes up difference in rearend ratios and tire sizes. I did a search on this site for speedometer gear info. Go to this site for help on selecting the tranny gear;
http://www.moparts.org/Tech/tech/pages/speedo.html. If it's only off by 5 mph, it's not worth correcting. Good luck.
