Looking for help in identifying the whining/humming sound my 2011 Explorer XLT Auto Transmission(60250miles) makes when I take the foot of the gas(accelerator). The minute I touch the gas pedal, the humming or whining stops. it is very low pitch, but it bothers me when the radio is not on. When the car reduces speed, and it is idling down, it makes that sound until it comes to full stop. I researched online and saw it could be a transmission issue. As a matter of fact, I have tested by taking the foot of the pedal, and putting the car in N(Neutral) whiling it reduces speed, and the noise does stop. The minute I put in D(drive) and the car is still reducing speed, the humming/whining starts until it comes to a complete stop or I put the foot in the gas pedal again. it sound like a transmission problem! It shifts smoothly. What could be the source of the humming and if the transmission, what could be the problem? Thanks !