Well technically, if you go by what those letters stand for, then yes if 4 wheel can/are being driven then it'* a 4WD. 4WD means 4-four W-wheels D- driven. Whether or not it'* at the same time, all the time. AWD refers to A-all W-wheels D-driven. It'* more a labeling thing than anything, but in all retrospect AWD means all wheels are being given power, in SOME percent, at ANY given time. 4WD means that 4 wheels are CAPABLE of recieving X-amount of power at X-defined time. General rule of thumb here, AWD requires no driver input, 4WD does.

Well.Jeez ya guys can confuse somebody. Alec has it the best. Also 4WD doesnt really drive all four. Each differential has limited slip just like a RWD. So only one tire front and back are pushing; shifting to the other side if one loses traction. AWD gives power to all wheels with a variable torque transfer at each end. I wasnt gonna drink tonite.....but now I need a beer.

You could have gotten away with this had you not said "always" Remember, always is a powerful word, because there is ALWAYS and exception to the rule.

Hyundai'* (start bashing) have a very unique 4WD system. The irony is in how it goes against a couple of a few people'* points.

First, Hyundai Santa Fe'* are 4WD vehicles. Get inside, no where will you see anyway for the driver to control anything that has to do with power to the drive wheels (besides a gas pedal). That is the first thing.

Second, the system does not split the power evenly. There is a bias. 99% of the time, the Santa Fe is front wheel drive. The other 1% it is 60/40 split between the front wheels and the rear wheels respectively.

Just thought I'd toss that out there.

Oh, BTW, not very many 4WD vehicles are 50/50 split. I'm pretty sure Jeep'* are in the minority when they have "part time" 4WD which does evenly distribute power. This works well when there is little traction, but hop on the road with a 4WD vehicle with 50/50 split and it will not last more than a few miles without doing damage.[/list]

I work for www.gearcentregroup.com
I sell transfercases, differentials, lockers and all that stuff ALL DAY LONG lol

Many different variations of Transfer case, mainly made by Borg and Warner or New Process.

A stock 4wd truck, without a diff lock in the front or rear is really only a two wheel drive, one wheel has power in the rear, one has power in the front, as both differentials are "open". The Inner nest kit it both diffs will couple and power away from a wheel that gains to much traction, usually. This is why they wear out, and people chew splines and what not on there axle shafts.

AWD basically means it a full time "4x4" vehicle, usually Fully independent drive/suspensoion, much like say on a Chevy Astro van say for instance
GM 7.25 CORP diffs front and back. This gives a better traction advantage, especially on more say gravel.

Thats the gist of it...i could go into Vacuum operated diff locks/electric diff locks, were a small shift collar is engaged to lock that differential into power mode, as, some vehicles regardless of t-case shifter position, still allow for the front driveshaft to rotate.