After a couple miles of drive and when come to a stop, either at stop light or parking lot, I can hear some kind of intermittent knocking from the cabin.

Had my wife drive. Back to parking lot, she holds the brake at DRIVE position. Open the hood, knocks is at the fan area. If the brake is released (while on D), knocks disappear. I used a HarborFreight stethoscope to listen to the area (alternator, pump, fan bearing, engine). No knocking. The only area I can't test is the rotating fan clutch.

Could it be the fan clutch need to be replaced or else? Strange is it only HAPPEN AFTER A COUPLE OF MILES OF DRIVE, BRAKE AT DRIVE POSITION.

Any suggestion?