l mean like Subaru's, which have 4 wheels, yet say they have ''all wheel drive''

All wheel drive is like a 4 wheel drive but it is always on, while in a 4 wheel drive you have to activate it. All wheel drive use most Gasoline.

All wheel drive is a system that provides power to all whells all the time. it cannot be disengaged. 4 whell drive typically is used in truck and comercial aplications or rugged SUVs. 4WD can be disengaged or selected at the client needs. Typical SUVs like Acura, Subaru, Mercede-Benz, are All wheel drive.

standard (two wheel) has one tire (front right for front wheel drive) that all the engines power goes to (you notice this when you are stuck in snow or mud and one tire is spinning like mad, 4 wheel drive has 2 tires spinning front right and rear left, and all wheel drive all wheel evenly get the torque and energy from the engine evenly distributed (those guys that cross the desert in baha races use these cars)

All-wheel drive is also known as full-time four-wheel drive.

With conventional four-wheel drive(or 4WD), a transfer case can be shifted to allow traction from all four wheels, or only the rear wheels to be driven (2WD) for better fuel economy & for reduced wear on the driveline when traction from all four wheels is not needed, as when driving on clear, dry pavement.

In a full-time four-wheel drive vehicle, like the Subaru, four-wheel drive is engaged at all times, & u have no option to shift the transfer case to 2WD. Full-time four wheel drive is becoming more popular among high performance vehicles because it allows for better steering traction in rain & bad weather. It does, however reduce fuel mileage, & cause more wear on driveline components.

no difference, in terms of functionality. power from engine is distributed on all 4 wheels of your vehicle so you have a better grip on the road.

the only difference is that you can switch from 4-wheel to 2-wheel on a 4x4, while ''all-wheel drive'' or AWD is full time. such like the audie and subaru vehicles and the toyota land cruiser.

other vehicles you have a choice of 4 or 2 wheel drive.

The Subaru is All Wheel Drive system is very sophisticated. All of the wheels do not necessarily ''drive'' at the same time. It can act like a front wheel drive car or a rear wheel drive car depending on surface traction and what you the driver are wanting to do at the moment.

On the STi version of the WRX it actually has what they call DCCD or driver controlled center diff, which means you can manually change the amount of torque going to the front or rear tires at your discretion. It also has an automatic mode during which the computer decides where to send the power. This is also standard on the '05 and up Mitsu Evo's. Very cool trick indeed.

A small note of clarification the answer saying power goes to the right front wheel. That is true if the wheel CAN spin. If it cannot spin power is applied to BOTH front wheels. the reason the right tire usually spins is that ur weight is over the left tire, so the one without weight on it spins. If u have a limited slip diff, pwr is still applied to both front wheels unless u floor it & cause the clutches to slip. (not good. the clutches will eventually burn)
If u want to verify this, set up ur car with the right front tire on dry ground & the left front tire on something slick, get in, put it drive, & apply the throttle. You will see the LEFT front tire spin, even though ur weight is on it.

l have owned both a 4WD Suby and AWD Suby and they got exactly 30mpg, l do not know where people get the idea that AWD decreases gas mileage. The 4WD (1987) had a 1.8 litre engine as well, the AWD (2001) has a 2.5 liter and still gets 30mpg. Ahh. The Beauty of All Wheel Drive!

Each wheel is drive function independently whereas in a 4WD, all the wheels move at the same time and at the same ratio, functioning on dependent gears.