B4 I got on the freeway tonight i hit the tow/haul button and the OD light with the line through it came on.........truck would not shift into OD.........got off the freeway shut the truck off and when I started it again...about 5 minutes later the light was gone and everything was ok.........anyone know why the tranny does this?

It will shut the the OD off if you hit and hold the tow/haul button for about 2 seconds. Thats how it works.