What is the differential made of? Ordinary differentials are composed of planet gear teeth, planet carrier (differential housing), side gears and other parts. It is normal to be confused, because he is indeed a relatively complex institution.
Just remember that when there is no speed difference between the left and right wheels, the planetary gear in the differential does not rotate, it rotates synchronously with the left and right half shafts as a whole. When the vehicle turns or the left and right wheels have different speeds, the planetary gears in the differential also start to rotate, absorbing the speed difference generated by the left and right wheels.