My experience with it in trucks I have plowed with (nothing real new), is that it’s not the same as awd, but as “Gressy” said, just automatically engages the part time 4 wd mechanism. When in 4 wd the drive train bias is not as variable as a true awd and therefore may have negative high speed handling quirks. Still, a decent functional alternative to staying in 2wd or 4wd all the time for truck application.