My driver's side bushing sounds like it needs to be replaced. When I go over a speed bump(mound), the driver side tends to make a thunk metallic sound, that wasn't there before. The front passenger side goes over the bump without a sound. If it is the bushing, which need to be visually verified ( and which I have not replaced before since I got the car about 30k miles ago), I thought you can replace one side at a time and not both?

Thanks.