I have an F-350 4x4 with a 7.3 diesel in it. I bought it new in 1997. It now has 120,000 miles on it. Just lately when I am stopped at a red light and you get the green to go and I accelerate, the truck does not move right away. It seems like there's a slight hesitation in the transmission before it moves. It only seems to do this when the transmission is at operating temperature. When transmission is cold it seems to work fine. Other then that problem the transmission works like it did when it was new. Shifts nice and smooth. The truck was never used to haul heavy and trans fluid and filter were changed regularly. Any ideas on what wrong or how to fix this would be helpful.

Thanks Scott