2003 Sport trac Transmission problem
 

2003 sport trac transmission. I get in the truck drive half mile to stop sign and the transmission seem to go in neutral. After about a minute it goes back into gear and works fine. This seem to only happen while the engine is cold. It doesnt happen everytime just seem random. Also a few weeks ago while running 60mph it seem to jump out of gear and rev. This has happen 2 times. What could be causing this problem ?

The signals to the trans need to be watched/recorded closely to determine if there is any fluctuation in gear selection If none are observed when problem appears that would confine the problem to the internals of the trans. And that could involve the valve body.