This truck is an NXT'ed version of the Off Road Truck (Technic #8273). I tried to keep it as close to the original model as possible. The four wheels in the back are all powered by one motor and like in the original, they can tilt. The video below shows the truck being remotely controlled by another NXT brick over bluetooth. More pictures, a CAD design and the remote can be found here. If you want to build your own nxt'ed truck, email me for the MLCAD files.