An object can resonate or rattle when the appliance operates. That observation helps identify external sound transmission, although it does not certify every freezer function.
What the observation tells you
Objects should not be stored where the manufacturer requires clearance or where they could fall. Pressing on the appliance or weighing down a panel may hide a noise while creating a ventilation or stability problem. A chest-freezer lid also needs unobstructed safe movement.
A useful next step
Move loose items to appropriate storage and keep required gaps clear. If an unfamiliar mechanical sound remains, describe it separately from the external rattle.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.