How Do I reset the computer chip on my 1997 Ford Explorer??

How do I reset the chip on my explorer??

It's a 1997, 4.0 SOHC V6. (140k mi)
The reason I want to do this is, I just had the transmission rebuilt (o/d lights kept flashing and then my car stopped moving) last week.  It drove fine all through lastweek until yesterday.  Somehow, the 4WD hi & 4WD lo lights keep flashing at odd intervals!  I took it to the mechanic and ofcourse it didn't flash when I was at the shop!  I wanna try resetting the chip and if that doesnt help I'll take it back to the shop!

Thanks!

 Unplug and clean your battery cables - leave them off for a few minutes and reconnect them. If that doesn't work you will need a code reader that erases the codes. ( I think they're like $80 - maybe less).