The truck will drive and pull fine for weeks at a time then I have the following issues.
1. I'll drive down the road and the truck will slip out of gear and rev up. I can let off the gas so the rpms drop and it will go back in gear.
2. I'll drive down the road and the transmission doesn't completely disengage but the rpms will creep up and down, up and down. For example 70 MPH rpms will be 2300 most of the time. When this happens they will jump to 3000, stay there for a minute, then drop back down. This will repeat for a while. The next time I'm on the highway it will run fine.
I have had my truck to 2 different transmission shops and they tell me the transmission is fine. Apparently it's the first year the tranmissions had computers to the codes it provides are ok or they didn't have the equipment to read them.