Thanks to everyone for the helpful replys. Stan, very good information.
Everyone seems to understand the noise I am describing. It does seem to have increased in volume after my "high speed drive" on the Interstate. I can hear it when the windows are up.

Stan, I wondered about loose windings or laminations causing this. My Dad was in the mining industry and all of the underground vehicles were electric. The noise reminds me of the noise those machines made when they had loose windings or bad brushes in the electric motors. So that is what has me a little worried.

I can't imagine that Toyota would allow an over current condition at high speeds that would damage the motor but.....I don't know.

Do you guys think that I should have the dealer take a look at it? I just have nightmares about some guy banging on the electric motor with a hammer or something.

I have to admit I love the noise, at least I did before it got louder. Now I worry some damage has been done.