The differential is the part on the rear axle that allows you to take a corner. Have you ever imagined how it functions? The Chevrolet Motor Division of General Motors Sales Corporation tells us how differentials work in this classic video Nitrous Oxide Boost- How it Works One of my close friends is an expert mechanic and very experienced when it comes to custom car optimization. He recommended a very good informative visual explanation of how limited slip differentials (LSD) work and it can be seen here. I haven't seen a better explanation, so take a look and learn.