Whining Chevy Lumina

I have a '99 Chevy Lumina 3100 V6 with 54k miles. There is a loud, high-pitch buzzy whine that changes pitch with engine RPM/transmission speed. The whining noise is only evident while the car is accelerating (forward or reverse), and above 5 mph. I removed the serpentine belt and drove it briefly (500 feet) - the noise is still there without the belt. I figure it’s safe to assume it’s not the power steering pump, alternator, H20 pump, idler or belt tensioner. The transmission has had regular service, and shifts smoothly in all gears (fluid is clean and level is full). There is only a slight raspy “scraping” noise in park or neutral, which becomes almost undetectable when shifting to drive or reverse with the brake still applied.

I’d be wondering about a bad mount