Never understood the difference between All Wheel Drive (AWD) and Four Wheel Drive (FWD)
basically 4wd and awd are "technically" the same deffinition. it requires the vehicle to have a transfer case of some kind and the "ability" to send power to all 4 wheels of the vehicle...now i'll get into why i used quotation marks. They are "technically" the same because yes its true a hummer and a little subaru may have a transfer case and the ability to supply power to all the wheels, however the term AWD is usually given to thinks like cars and minivans opposed to the heavier duty versions like a pickup or a hummer. usually 4WD is also placed on vechicles that have a selective transfer case, meaning they can go from 2wd to 4wd via a selector. awd typically stayes engaged all of the time and is much lighter duty.....now both a 4wd and awd vehicle use spider gears to turn multiple wheels and axles, but on a 4WD they're much tighter and grip much better so more power actually makes it to the wheels. this is why its not easy or reccomended to turn on dry pavement with a 4wd, too many binding parts trying to turn multiple wheels.hence a 2wd selector, in awd the spider gears slip much more and make it very easy to turn reguardless, only problem being they also slip when overpowered or in slippery conditions, making awd much less capable or offroad ready than 4wd. while awd is decent for normal light snowing conditions please don't take your subaru through the woods because a big 4wd chevy or dodge will have to pull you out.lol there's the highschool/ overelaborate answer for ya!