65000 miles on truck on a long trip recently it started falling out of over drive after a slice easing in load like after going down hill and easying back in to throttle . Does it on cruse and by foot rpm increases 200ish then slides back in overdrive or back into lock up in rolling hills does this repetedly tried serching nothing came up thanks

 

When you lift off the go pedal the torque converter unlocks. When you ease back into the pedal it will relock after a couple second delay. This is what you are seeing and it is the way it was designed to operate.

 

Thanks I was hoping it would be the case on my trip I hit a section of rolling hills it was very notable I got to worrying thanks again