Grinding sound in Park

Some of the items that can cuase this are,flex plate,inspection cover,oil pump,flex plate bolts loose.I would remove all belts and start the motor and see if the noise goes away.If the noise is gone in all gears,except park it could be a minor problem in the bell housing.It could also be major too until you remove some panel and see.Is the starter tight,bellhousing bolts tight.Check them all and the items mentioned and post back.Mrmopartech