Thanks Brian, it is a tamiya gearbox that I seal up to keep dirt out.
It is a blast to operate. I didn't want to get it dirty because I might sell it so, I figured loading stone would show how much power and agility it has...I just finished it this afternoon and haven't gotten the hang of running it smoothly yet.
http://www.youtube.com/watch?v=ZwDHgERW5xk