Worth an hour?
 

Only if you want to know more about differentials than you might know already..

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At 38 minute the torsen gleason (w/o the air lock), preferred diff for my road race cars.
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This video is on the other end of the spectrum - it's an outstandingly well-done video that will make the operation of a differential intuitive to absolutely anybody. My partner, who is an educator and knows nothing about cars beyond what she's learned from me, loved it from an education standpoint and has used it in a talk.

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