put my caddy in gear today sounded like a siren going off much like a power steering pump but louder only does it under load not in neutral or park or when coasting no loss of power no miss some people said it sunds like the tranny pump is going tranny fluid and filter changed 3 thousand miles ago (every 15 thousand) not low not burnt. car has 122k. noise travels sounds like its coming from under the hood but hear it under the car and behind the car cant pinpoint it.any ideas?

A damaged tranny filter seal can do the same thing. It's a cheap place to start. Drop the pan and look that seal over close. I have seen them do it right after a filter change. It happens...