I have a 5.3l 2010 silverado with the 6-speed tranny. Recently I just noticed when the truck is started once already warm, I hear a whine near the center hump between the driver's and passengers front seat.

I have no radio on or HVAC system on. The sound changes with the RPM. IT goes away after about 30 sec to 1 minute.

Any thoughts on what this could be? The dealar replaced the tranny filter thinking ti might be restricted. No change, truck only has 9000 miles on it.

Looking for any advice. Thank you!