One problem related to overdrive light on has been reported for the 1996 Ford F-250. The most recently reported issues are listed below.
The overdrive light keeps flashing and you can reset the computer and the transmission will shift fine until the overdrive light comes on. It has been tested and it shows there is no reason for it to be flashing. Have had it in the shop now 15 times and even special technicians looking at it and can't figure it out. I don't want to loose my transmission.