What are the differences among 4WD, All Wheel Drive, 4x4, and 4x2?!!!?

Question

I'm looking into purchasing a sport utility, and I don't understand the differences, nor has anyone been able to clearly explain the differences, if any?

Thanks, and I appreciate any help.

Answer 1

it isn't as complex as it sounds, but describing it without pictures isn't as easy as it sounds:

For your ease of understanding, I'm going to use some gross oversimplifications.

Imagine the capital letter "T" and attach wheels to the ends of the horizontal bar, so that the bar intersects the center of each wheel, and if you drag the assembly by the vertical bar (straight down the page), the marks left by the rolling wheels will be parallel to the vertical bar.

The horizontal bar represents a drive axle (as opposed to a steer axle). This was the common configuration when cars became popular, and most cars still have 4 wheels -- so we refer to the front pair of wheels as being located on the front axle, and the rear pair of wheels as being located on the rear axle -- even when there isn't an actual axle connecting them (as is commonly the case with independent suspension).

In this example, the vertical bar represents the driveshaft, and it's like what you'd see if you were looking either directly down from the top (or directly up from the bottom) at the drive axle assembly.

4x2 = "four by two" = 4 wheels, 2 of which (at most) are powered
This is also called 2WD ("two-wheel drive"), and if you run across a stickler for accuracy, it may be called "1WD" or "one-wheel drive" if an open differential is used.

Engine power goes through a transmission and is distributed to the wheels of one (usually the rear) axle. Inside the axle is a "differential" that allows the tires on the outside of a curve to turn faster than the tires on the inside of the curve.

Ordinarily, vehicles come with "open" differentials, meaning that both wheels on that axle are only powered when the brakes are slightly applied.

There are a variety of locking differentials that are suitable for use in the rear of a vehicle, and some are installed as optional equipment by the vehicle manufacturer. For vehicles used often on the street, a popular option is to use a Torsen (a trade name that stands for "torque sensing") differential.

4WD = "four wheel drive" = 4 powered wheels

4x4 = "four by four" = 4 wheels, 4 of which (at most) are powered

For ordinary passenger vehicles, 4WD and 4x4 mean the same thing: engine power goes through the transmission, and then through a transfer case to the front and rear axles, where it is distributed to the wheels.

Note: Commonly, 4WD systems transmit 50 percent of the power to the front axle and 50 percent of the power to the rear axle; that ratio can't be changed.

Also note that the front and rear axles each contain a differential, as described above. Ordinarily, 4WD vehicles come with "open" differentials at both ends, meaning that you only get TRUE 4WD with the brakes slightly applied. Also, if the vehicle has locking hubs, you're not getting 4WD if the hubs aren't locked.

A popular and very effective on/off road combination is a Detroit Locker (trade name) rear differential and a Torsen (a trade name that stands for "torque sensing") front differential. With a locking differential, if you're not going around a curve, the power to that axle is distributed equally to each side of that axle (you don't have to apply the brakes).

There are locking differentials that will prevent the tires from turning at different speeds any time the locker is activated, regardless whether the vehicle is turning, but they're uncommon except on heavy trucks (like 18-wheeler size trucks) and equipment.

AWD = "all wheel drive"

I'll skip the history lesson and give the modern meaning:

It's similar to 4WD, except there is a "torque bias unit" (sometimes also called a "differential") between the front and rear axles. Generally, this device changes the percentage of the engine's power that reaches the respective axles.

For rock crawling and serious offroading, a 50/50 split (front/rear) is usually considered best -- but for spirited driving and road-holding, a 40/60 or even a 33/67 split (front/rear) is usually considered best.

Except for some competition vehicles, AWD torque bias units are automatically controlled either mechanically or by computer.

Now for the tough part: *generally* speaking, 4WD drivetrains are more rugged, but 4WD vehicles typically get *much* morse fuel economy than their AWD counterparts. AWD vehicles are usually more versatile, and handle and drive better on the road than their 4WD cousins -- but they aren't built to handle serious offroad terrain.

FWIW, I've seen more stuck 4WD vehicles pulled out of holes by my dad's '68 F100 pickup (4x2 Styleside, 8-ft bed) than I can remember to count -- and I've seen my dad go places (with me in the cab) in it that people with 4WDs couldn't go. And, all else being equal, a 4x2 will get better fuel economy.

Know your vehicle's limits, and know your own capabilities -- and don't exceed either ;)

Answer 2

Thats a loaded question 4x4 means all 4 wheels turn at the same speed, with locking differentials, that is. Now all wheel drive means just that all wheels are used to drive the car or move the car anyway. 4x2 means there are four wheels on the vehicle but only two drive or move the vehicle. It all depends on what your going to do with this vehicle. 4x4 = Muddin. On the other hand. All wheel drive means safety in all weather on roads of any kind.

Answer 3

There are huge differences. Ok If it says 4x4 or 4wd, it means u have the option of having all 4 wheels power the vehical via a transfercase. A transfercase allows you to switch from 4wheel drive high, to 4 wheel drive low(use one of these if u get stuck in the snow, mud etc), to 2wheel drive high(aka 4x2, this is what u would use for normal street driving). If u have All-Wheel Drive It means that 4 wheels are always powering the vehical, but it is computer contolled so that if one side of your vehical looses traction, it sends power to wheels with grip to power the vehical and get it back on track. 4x2 means that only 2 wheels (usually the rear) power the vehical at all times. Basically 4x4(same a 4wd) means 4wheels, 4 of them can power the vehical. 4x2 means 4 wheels, but only 2 of them can power the vehical.AWD means exactly what it stands for...ALL WHEEL DRIVE

Answer 4

4WD, all wheel drive, and 4x4 are all the same thing it just means that when you accelerate all the wheels push the instead of two. but ive never heard of 4x2, i assume it just means that only two wheels will move the car the other two are solely for stability.

Answer 5

"Although in the strictest sense, the term "four-wheel drive" refers to a capability that a vehicle may have, it is also used to denote the entire vehicle itself. In Australia, vehicles without significant offroad capabilities are often referred to as All-Wheel Drives (AWD) or SUVs, while those with offroad capabilities are referred to as "four-wheel drives". This term is sometimes also used in North America, somewhat interchangeably for SUVs and pickup trucks and is sometimes erroneously applied to two-wheel-drive variants of these vehicles.

The term 4x4 (read either four by four or four times four) is used to denote the total number of wheels on a vehicle and the number of driven wheels; it is often applied to vehicles equipped with either full-time or part-time four-wheel-drive. The term 4x4 is common in North America and is generally used when marketing a new or used vehicle, and is sometimes applied as badging on a vehicle equipped with four-wheel drive. Similarly, a 4x2 would be appropriate for most two-wheel-drive vehicles, although this is rarely used in the USA in practice. In Australia the term is often used to describe utes that sit very high on their suspension. This is to avoid the confusion that the vehicle might be a 4x4 because it appears to be otherwise suited to off-road applications. A 2×4, however, is unambiguously a piece of lumber."

Answer 6

Forgive my ignorance. Can a front wheel drive SUV have the 4 x 4 option or are all 4 x 4 SUVs rear wheel drive? Thanks!