Torsen diff are all gears inside. "Torsen" is for TORque SENsing. The design of the gears, gear arrangement, gear type determine the how it distributes the torque.

They are sort of complex in details. Read directly here: http://www.torsen.com/products/products.htm or find some other manufactures literature for a first hand expanation in plain english.

There are no clutches or cones that slips against something. Nor is it a ratcheting type like a Detroit Locker. Supposedly Torsens don't wear out.