When driving the truck for the first time of the day I have this problem. When it shifts threw all the gears and gets into overdrive it starts a bucking. I can accelerate to make it downshift then let it shift back into overdrive and bucks again. I go threw this 4-5 times overdrive, downshift overdrive and then all the sudden it clears up and runs smooth in overdrive w/ no probs. All other gears shift fine. Truck is at full operating temp when this happens. Not like I just jump in it cold and romp on it. Anyone experience this?