Transmission hesitates.

When I first start my truck up some mornings it doesnt shift properly. I believe its in second gear and it will go up to 3500 rpms sometimes higher before shifting. If i keep it steady it will eventually shift after 15-20 seconds or so. I know this isnt normal for my truck. The transmission fluid was serviced about 60k miles ago but I wasnt the owner then so im not sure if it was flushed or drained and refiled. Im wondering where I should start diagnosing my problem. My truck has only 175k miles so im hoping to get a lot more miles out of it before I have to do tranny work.

 

My auto transmission does similar, always has. I'm at 170,000 miles.

It usually only goes to about 2500rpm then I ease off the throttle for just a second and it shifts. As soon as it's warm that goes away.