Loud whining/humming noise, seems like metal to metal on 2005 Chevrolet Uplander

A loud whining/humming sound is coming from the driver side of the engine-front wheel drive. At times there is no sound but once it starts it wont stop until the engine is shut off. There are no warning lights on, and the car does not have to be driven, it will make the sound in park. Source of the sound?

Asked by for the 2005 Chevrolet Uplander
You may have possible transmission pump or bearing noise, check fluid and if good may need to take to transmisssion shop.
Thank you very helpful, today while checking further into it I found that the noise either goes away or increases for some time when going from and back to park, neutral, reverse and drive. I'll have it checked by transmission shop, Thanks again.