Engine oil pressure is 60 @ startup and drops to 50 @ operating temp. She's due for an oil change this weekend - will inspect filter.

However, given the variables listed in my first post, I have my doubts about anything engine-related. I just don't know anything about automatic trannys to know what would cause this sound that presents only after the thing is warmed up after driving a bit.

I was hoping somebody w/ trans experience could shed some light on the inner workings of the beast.