The difference between All-Wheel drive & 4 Wheel drive

[LDUBS]

4 wheel drive; example Chevy Silverado and I imagine other pick ups, there is a switch to run in auto (similar to all wheel drive), two wheel drive, and 4 wheel drive Hi or LO (locked).

At least that's my thoughts..

What you describe here is exactly how my RAM truck works. So far I've had it in 4WD auto, 4WD hi & 4WD low just to make sure it works.