Over the course of regular usage, the freezer can make some rattling noises that are part of its normal operation. The most common causes of this noise are the flow of refrigerant and the water line. If the cause of the noise is one of these, you can do nothing about it because it is completely normal.
Something Sitting Inside Freezer
Open your freezer door to inspect the items you have inside. Two items may be positioned against each other causing the rattling noise, or an item may be sitting awkwardly that is causing the noise. Move some things around in the freezer to try to stop the noise, if you suspect it is coming from something inside the unit.
Something Sitting Outside Freezer
Look above the freezer to determine whether you have anything sitting on top of it. If so, this can cause a rattling noise if the freezer is vibrating, which makes the item sitting on top vibrate. Moving the item off the top of the freezer should stop this noise.
Refrigerator Not Stable
If your refrigerator is not sitting level on the floor, it can cause a rattling sound from the freezer. If the unit is not stable, the items inside the freezer may not be stable either. You can lower the base grille to access the adjustable leveling feet. With the assistance of a friend, adjust the legs with a wrench to get the refrigerator in a stable position and stop the rattling from the freezer.