Finally a post! A brilliant (albeit very old, but still relevant) demonstration of how an open differential works. Thought it was a nice thing to share
There are several types of differential - open, limited-slip or locked.
Open differentials are what are demonstrated in the video - they are attached onto the end of the prop shaft and then control the speeds of wheels rounds corners, in bump e.c.t
A locked differential is simply a spool - just a solid piece of metal, with a sprocket attached.
The final type is a limited slip differential. Unlike the other two these come in many forms. They work very similarly to the open differential, but only under certain conditions. For instance a viscous differential (one filled with oil that becomes more viscous the warmer it gets) only locks at high slip angles, otherwise it acts like a normal open differential. Another type - the torsen uses worm gears which will lock at higher speeds, so under low loads (so low speeds), it will act like an open differential. Another type is the plat differential which is effectively a differential with a clutch built into it - it uses several methods to help lock the wheels at various speeds, but similarly, the faster and more load you carry, the more likely it will lock
