today as I was driving my 2001 f-350 7.3 my speedo went and at the same time the overdrive light won,t stop blinking and the speed control wont work,I brought it to the local tranny repair shop and the computer diagnosed it as the speed sensor in the diff.they proceeded to change it and it still did the same thing and the computer still diagnosed it as the speed sensor,at that point they were dazed and confused,(typical key west mechanic) and munbled somthing that it could be the speedo needing recalibration!!!!ant real help would be appreicated!!are there 2 speed sensors?everything else works great,overdrive switch works,tranny shifts fine.