I drive an old Buick park avenue (1991) and these cars were literally marketed for how quiet they are, on top of many things.

While driving home it sounded like someone stole my catalytic converter… extremely loud but I checked and it was still there.

Has anyone else experienced this? What could it be?

Checked the car In park / neutral and it didn’t make the same sounds so I’m praying to God it isn’t my transmission.