My fridge makes a bang noise when it shuts off

 Sorry to say most times this is a faulty compressor. A compressor is a electric motor and pump mounted from springs inside the black dome, if one of these springs stretches or breaks the motor and pump hits the outer casing dome and bangs when it shuts off. Other things to check for, tubing touching one another, something fallen behind the fridge, condenser fan motor blade hitting something, defrost condensing pan out of place.