1999 Dodge Durango transmission hesitating

I have a 1999 Dodge Durango, 8 cylinders, with 200K miles. For the last 6 months the transmission is sometimes hesitating shifting from 2nd to 3rd. I have to play with the gas at around 25-2700 rpm before it smoothly shifts into 3rd. Downhill or when accelerating slow it shifts OK. It also seems to shift much better when the weather is cooler and the engine is not hot.

I changed the transmission fluid, filter and speed sensor, but it did not help.

While it does not seem like an emergency I like to see what I can do next to fix this problem before it gets worse. Any hints, tips or ideas what else I should look at?

I would not worry about it too much. I owned a 2000 and 2002 Dakota and neither one of them would shift into 3rd while going uphill unless you suddenly let off the accelerator. I got used to it and neither one of them had any transmission troubles at all except for this little quirk. A Dodge mechanic told me one time it had something to do with how the shift points were calibrated when the transmissions were designed.