transmission slipping

[jimbo63]

I have 2007 Ford Explorer sport trac 4.0 automatic with 104,000 miles my problem is while driving my transmission will not go to next gear range the rpm goes up and truck revs up.it seems to be slipping but not all the time.anyone know of anything that could cause this or does it need replacing or a rebuild.thanks for any help.im getting to dislike my truck immensely

 

[Tech By Trade]

Which gears are missing? second and fifth?

 

[jimbo63]

I'd say 4 and 5 gear it happens around 60 to 75 miles per hour.im supposed to take it on long trip and don't trust the truck

 

[jimbo63]

Which gears are missing? second and fifth?

I'd say it's 4 and 5 gear when I'm driving 60 to 70 miles per hour doesn't seem to do it at lower speeds it just seems to rev .im taking this on a long trip and I don't trust the truck

 

[Tech By Trade]

a sign the servo bores are shot. the od bands that are driven by them.