I've seen that on youtube; it's a chain drive and it does go up some pretty gnarly stuff. IIRC it's got a 302 and a C4 or something but each leg/arm is controlled individually through hydros. Pretty inventive to say the least.

Here's the link:
http://www.youtube.com/watch?v=w_F7QrR4Ur8

>>Dan

The listed weight is 5900 lbs.