Articulated Steering

I built this to test the idea of 4 wheel steering.

My challenge is for someone to build this using the NXT. It would probably be easier not to make the middle wheels move back and forth. But it would be interesting to see how you would power the axle while it moves. If you do build it with the NXT please put it on NXTLog and comment to tell me that you put it on. Also put the tag of sixwheelcar .

NXJeep

This is a work in progress my Jeep using NXT.
It has 4 wheel drive and articulated steering but it
isn't fast because there is a worm gear in the drive chain.
I am having a hard time replacing the worm gear to make it go faster. Because currently it is slow. any ideas would be kind.