I have a 98 ram 1500 and have had 35" tires on for a while and just installed 4.56's and was trying to get this thing recalibrated. The dealer is telling me they can only configure to max stock tire size and max differential ratio. the speedo shop tells me i need an in-line box to convert the signals, but its not the speedo im trying to fix, its the tranny shift points. My tranny seems "confused" at times with less of a load on the engine as before and shifts a little off. I have reset the computer which did help but is still a little off. Any suggestions? Maybe a programmer would be the best way to go?