I've read a lot of posts about the blinking OD light and got mine read today, it came up with a P0503, Vehicle speed sensor (VSS) intermittent. I've looked at the wiring harness to see if there was somplace it may have chaffed through the Chafe wrap and could not find anything. I've also changed both the speed sensor for the ABS in the rearend and the VSS on the tranny itself. I've also had it worked on by a tranny shop because when I changed the sensor the plastic gear on the output shaft of the tranny had either broken or slid backwards. It seemed that after the shop worked on it, for a few days afterwards the code did not come back. My question is, is the gear on the output shaft of the tranny supposed to have some movement on it? or is it supposed to be tight? and could this gear being a little loose be the cause of a P0503 VSS intermittent? Oh yeah, and everything works as advertised. No hard shifting, it goes in and out of OD when it's supposed to, turns on and off with the OD button.