1994 Ford Taurus transmission

I have 1994 ford taurus 3.8 L engine. The transmission works fine when cold, but when hot it does not want to engage drive or reverse. Going down the road shifts fine, but when I have to stop at a red light (after it gets hot) I have to punch the gas to force it in to reverse then go back to drive where it will shift easily then. But it will not go back to drive unless I force it in to reverse first. When forced in reverse it goes in gear hard. Then it goes down the road fine until I have to stop again. When I shift to drive when cold it thumps into gear and right before it starts getting too hot it will thump back to drive when I stop. That is how I know it is getting too hot. Any help would be great.