Can someone explain what is a logical drive?

Can someone explain the difference between how my 4 wheel drive Grand Vitara works compared to my awd Aerio?

• Grand Vitaro is the model wth nothing to push, pull or anything to tell it to go to 4 wheel drive. Can't tell in weather we've had so far if it is kicking in or not. Aerio I traded in I could tell when it was working.

• Answer:

  Well a lot of four wheel/awd drive trains have electronic controls and actuators. Some systems work more transparently than others. The major differences between the two systems are as follows. The four wheel drive system is generally a more rugged system that can allow for a low range. These are the oldest designs and will work well for most driving. An AWD (all wheel drive) system is a lighter weight system that is used on vehicles that would normally be front wheel drive. They will not generally have a low range, although this will change this year when Chrysler introduces the Jeep Patriot cross-over SUV. This vehicle is based on the Dodge Caliber and uses a CVT with a low range. Go to www.allpar.com for info.