Pretty much the same as an open diff except that there is a center shaft connecting the axle gears with clutch plates that hold pressure on each other until there is enough force to make them slip such as a tight turn on asphalt. But in sugary sand (or if their spinning) there is not enough force to break the clutches tension so the wheels spin at the same speed. Now there area few different kinds of limited slip too. Ford has 2 large springs that are in the center putting pressure on the diff gears along with some carbon clutch plates. There is also another form of lsd that Im not completely familiar with but it uses and bunch of thin plates close together that are on a center shaft that have fine teeth on there outer edge. These plates dont touch, they use a special rear end lube and use the friction of that lube to move the plates together without haveing any actual physical wear on internal parts. Just burning up lube and replacing it. I believe that is how that one works.