Here is a flash animation of a car differential mechanisms.
This is under construction and explanations will be put soon. For the time being just click the buttons and guess what is happening.
This is confusing and time consuming animation. You may understand how differential is working, but you should have use your imagination a little bit to comprehend the mechanism.
Here is an excellent video I found in youtube about differential. Please watch it all the way, it will show a motorcycle show, just wait and see explanation for differential.
Here is another video by using Lego. In this demo notice that when the person rotates a tire the other tire rotates in apposite direction. I wanted to demonstrate this by using buttons RF and RB
In this video when the motor is running both wheel rotates in the same direction. However when the man holds one tire the other tire rotates much faster. This is demonstrated in our animation as S (Slip) button. Have you ever stuck in the mud or snow whit your car. One tire rotates but your car is going no where. This is because in one tire there is less resistance and it rotates by engine while the other one hold by ground.