Found this cool video series from 'Engineering Explained' digging into the theory of how differentials work which is nearly an hour worth. I found it educational.
Differentials - Explained:
Open vs Locked Differential - Explained:
Open vs Locked Differential - Torque Transfer - Explained:
^ haha, I tried to learn it out of a book first which melted my brain. After I watched these videos it made sense though.
I looked up similar videos trying to get a better grasp on shock absorbers as well and found these video's from Dyson Racing which were helpful to understand what to think about when setting up cars to steer well.
The last video "How a car turns" to me was the most insightful with a large part of the back end of the video talking about different diff setups being used on different tracks which explains some of the practical application of the theory videos on diffs I posted before.
SHOCKS 101: INSIDE A RACING DAMPER
SHOCKS 101, PART TWO: THE PHILOSOPHY BEHIND THE MAGIC
A lot of these sort of things are difficult to learn from diagrams and books, visual representations are a bit easier, but the best (I think) is to have a phyiscal look.
I learned about how diffs work from lego many years ago (I had a few sets which used an open diff)
And the Torsen I learned about by pulling apart a worn one and seeing how each piece interacts with each other. That and having a great chat with FLycasta on this forum when he built my diff (he pulled apart the centre and showed me all the bits etc and how they worked)