My 380 SEL does the same thing, w/ 200k on it. When cold, it flares very badly, in the 2-3 shift and sometimes a little in the 3-4. When it finally warms up, it goes away.
However, it takes a sec to find reverse. When it does, it finds it quite hard and tries to take off. If I wasnt worried about it, I would say it has the power in reverse to pull a house.
Please let us know how your transmission goes.