What does an STI Driver Controlled Center Differential (DCCD) actually do?

From 2004 all the way to 2021, the STI had a Driver Controlled Center Differential. This DCCD sits in between the front and rear differentials, and somehow controls how power is split between the front and rear axles. If you are doing an STI 6-Speed swap into a WRX or other Subaru, you typically want to install some kind of aftermarket DCCD controller so that you can get the DCCD to work. But what does the DCCD actually do? Does it really change how the power is sent to the front and rear axles? Can you disconnect the front axles from the car all together if you set it to open? We got a lot of questions about exactly what a DCCD does after our deep dive into a couple of aftermarket DCCD controllers, so for this video, we want to take a closer look at exactly what the DCCD does. Thanks for watching and Stay Tuned!