After a hour of driving the overdrive light started to blink on the shifter. Pulled over shut truck off, turned the truck back on, checked tranny fluid( was full did not smell burnt). It was not slipping and seemed to shift in the right spots. It never blinked again. Why would it do this?

 

Check your manual for what that means. It should give you an idea.

Also, you can try to pull codes for it.