One problem related to overdrive light on has been reported for the 1998 Ford Windstar. The most recently reported issues are listed below.
Last year transmission problems started again. I had the van in the garage again in December to replace the pump on the transmission after it blew apart and left me stranded when it wouldn't go into any gear. After 10 days the van would move again. Now again the transmission is slipping between 1st and 2nd. The van is famous for downshifting from overdrive into 1st or 2nd gear. The overdrive light is constantly flashing and not working.