No. A "all wheel drive" is all the time four wheel drive. A 4x4 or 4-wheel drive can be set to drive in two wheel drive or four wheel drive.
install a differential
Yeah, why not.
Check out the link in the Reated Links section, below. It has a list of parts required.
It isn't feasible to convert from two wheel drive to four wheel drive.
The transmission has nothing to do with the 4wd system and there is nothing to convert. Just install the transmission and you will be good to go if you have the right transmission.
The 2006 Nissan Armada comes with a standard rear wheel drive. The two and four wheel drives are optional.
To get a car to move the power from the engine has to be transferred to at least two of the cars wheels on the same axle. If these two wheels are at the front then the car is a front wheel drive, if the two wheels are at the back then it is a rear wheel drive. Some modern cars however now have mechanisms that deliver power to all four of the wheels at once, this is a four wheel or all wheel drive.
It means that power from the engine is transmitted to all four wheels instead of two. Four wheel drive is better for off-road driving, and two wheel is preferable for roads.
Yes, just as easily as two-wheel drive vehicles
Never! :) No seriously - why would you consider that? Just get a two wheel drive car!
Yes and no, you would need to have a two wheel drive rear drive shaft.
two wheel drives have two turning wheels. Four wheel drives have four turning wheels, meaning that it has twice the turning power of a two wheel drive.