What is making this louf grindin noise

When I down shift to first second or third to come to a stop its makin a real loud grindin noise I dont know if its the transmission or what it only does it when my feet are off the gas and the clutch and break arent pressed in. Than another thing is when I take off in first its makin a weird racket as well.O and when im stopping a squeakin noise cld tht be my shocks or what bc it is lowered