Drive Train

  Here is a picture showing how the power system is built into the truck. The drawing is a little crude, but it gets the point across.
  One interesting thing is that the battery pack is mounted upside down. That way the on/off button is easy to reach. It is not mounted firmly though. Basically it has a slot it is mounted into, and some small 1x6’s hold it up.
  One point could not find a way around was the linkage between the two sets of rear tires. Real trucks have a differential between the two sets. But because of size constraints, it could not be done on this model. Maybe if Lego comes out with a smaller differential pieces.