I have a new 2020 Tracker 300. It is an automatic. Today it started making a knocking sound. It will do this when it is in forward and reverse. It does not do it when idling. The crazy thing is it will make the sound when it is turned off and I push it. It will make the sound when it is in forward gear and reverse while pushing. It will NOT make the sound when in nuetral and I push it. Any idea?? Thanks. First time posting.