High Pitched whine or whistle at idle 02 Yukon 5.3

[Lew Schiller]

Just pulled in from a 10 hour drive and noticed an unusual high pitched whine - maybe whistle - at idle coming from underneath. Not noticeable under the hood. Noticeable from underneath...toward the front - transmission region . Reving in neutral does not change the pitch or volume level.
All accessories off.

Anybody?

Thanks!
Lew

 

[sumo]

Daym. Though it was another supercharger thread. Sure it’s not feedback from speakers? Bad amp can cause a nose like that even with radio off

 

[Erickk120]

If it's coming from the transmission area I would be afraid it's probably a tranny pump, and it only happens in idle correct? Check fluid level/color/leaks.