differentials

Hi Yesterday I did visit Honda service center for regular check up and they suggested on the transmission fluid, differential-rear, wheel alignment and of course sales pitch of changing all 4 tires. I would like to know the suggestible maintenance really required for the 32,500 mileage...

Okay, you may laugh at this videos intro or quality... But I've been to automotive college, and this is the best damned explanation I've ever seen on how a differential works! Enjoy =)