Difference between 4WD and AWD?

I know there is one, but not enough to talk to my boss about it. He has a Jeep Cherokee around 2-3 yrs old (newer body style but no squinty headlights).

Is it 4WD is all the time, AWD is when needed?

In my understanding, AWD is constant, 4WD has to be shifted in and out of operation.

I usually think of 4wd as having no center differential and AWD does. Someone will probably correct me, however.

They seem to be quite interchangeable these days. I think many of the AWD cars are now 'part time' IE only engage the front or rear wheels when the main drive wheels are slipping.

My '4x4' has a center diff, but its in the transfer case, and lockable.

Jerry wrote: Is it 4WD is all the time, AWD is when needed?

Thinking maybe I meant the opposite. My Subarust is AWD and just goes and goes, his Jeep is 4WD and he has to click a button or something.

IMO, 4wd has some form of mode selection and typically low range. It may or may not have a center diff, and if it does, it may or may not have a 2wd mode. AWD has no driver-selectable options, the system just does its thing all on its own.

in my mind it is more a game of "posi-trac" vs. "limited-slip" (i.e. no difference, just marketing), but in general it seems to be that AWD is associated with non-selectability and cars/car-based-SUVs, and 4WD is associated with selectability and trucks/truck-based-SUVs.

AWD is the marketing term for "this thing is stable on roads in snow"

4WD is the marketing term for "this thing can go off-road"

rslifkin wrote: IMO, 4wd has some form of mode selection and typically low range. It may or may not have a center diff, and if it does, it may or may not have a 2wd mode. AWD has no driver-selectable options, the system just does its thing all on its own.

That is how I see it as well.

4wd has lo range AWD does not

I think AWD is a marketing tool. Years ago Chevy had full time 4WD on the Blazer and they didn't call it AWD. As others have said, AWD pretty much works on its own. But, my company Explorer will automatically go into and out of 4WD or you can do it with a push of a button.

Our '08 Highlander says 4WD on the back. Really? It is an AWD vehicle. Seems that the marketing arms of manufacturers add to the confusion.

rslifkin wrote: IMO, 4wd has some form of mode selection and typically low range. It may or may not have a center diff, and if it does, it may or may not have a 2wd mode. AWD has no driver-selectable options, the system just does its thing all on its own.

Not always true - the AWD system in the Subaru STi has three driver-selectable modes.

STi center diff explained

Jeep is a good place to scope out drive systems as they have a few different ones.

jstein77 wrote:

rslifkin wrote: IMO, 4wd has some form of mode selection and typically low range. It may or may not have a center diff, and if it does, it may or may not have a 2wd mode. AWD has no driver-selectable options, the system just does its thing all on its own.

Not always true - the AWD system in the Subaru STi has three driver-selectable modes. STi center diff explained

That one is kind of a grey area between the definitions, I think.

Robbie wrote: AWD is the marketing term for "this thing is stable going over speed bumps at the mall" 4WD is the marketing term for "this thing can go off-road"

FTFY

I agree with the majority here. To me, 4WD is the driver has to select it. AWD has some sort of automated control.

If it's 2 or 3 years old and not "squinty" it's a GRAND Cherokee, not a Cherokee.

That's a peeve I developed while searching for a used late model Cherokee of my own. The Grand Cherokee and Cherokee are/were totally different vehicles.

Both AWD & 4WD can be selectable, AWD typically isn't, but AWD is going to provide a differential or viscous coupling that allows use on all road types. 4WD will only be used on loose surfaces, not pavement, and typically provides some optional gear reduction in the form of low range.

Our Cherokee (not Grand) has an NP242 transfer case which allows it to be, RWD, full time (AWD), locked 4WD High (1:1) or locked 4WD Low (2.72:1). Locked meaning 50:50 power split front and rear, not locked axle differentials.

4x4 is selectable 4x2/4x4 and usually high/low ranges. Awd is a car term meaning ALL wheel drive, no ifs ands or butts, it's all four spinning at the same rate all the time. Now sometimes people like Volvo have haldex awd which is fwd until it slips but that's a different story for a different time. Generally as a term, it's cars=awd trucks =4x4 but the select ability thing makes it actually 4x4 or awd. They used to have subarus that were 4x4 and not awd cause they were front biased until you clicked a button to make it 4wd

Duke wrote: In my understanding, AWD is constant, 4WD has to be shifted in and out of operation.

the way it was explained to me ... my Impreza was AWD ... so a center diff handled the distribution of power ... so no binding ..

my F150 has "truck" type 4x4 .. so that you need the wheels to be able to slip ... so you don't run it on dry pavement ...

I'm sure that's an over simplification of the answer, but should give you the basic, off the shelf info

If you can lock the center differential and both front and rear differentials, you have 4wd.

I would imagine that "AWD" means that any of the 4 wheels COULD drive if they have the traction.

I have distant memories of locking axle hubs and center differential in 4wd mode that made the truck very reluctant to turn once out of the snow.

NOHOME wrote: If you can lock the center differential and both front and rear differentials, you have 4wd. I would imagine that "AWD" means that any of the 4 wheels COULD drive if they have the traction. I have distant memories of locking axle hubs and center differential in 4wd mode that made the truck very reluctant to turn once out of the snow.

By that definition, almost nothing has 4wd from the factory. There's very, very few vehicles out there with locking diffs out of the box.

Storz wrote:

rslifkin wrote: IMO, 4wd has some form of mode selection and typically low range. It may or may not have a center diff, and if it does, it may or may not have a 2wd mode. AWD has no driver-selectable options, the system just does its thing all on its own.

That is how I see it as well. 4wd has lo range AWD does not

Not true either. My Subaru Loyale had genuine 4WD (Badges said so and you had to engage it and disengage it and couldn't run it on dry pavement in 4WD or it would tear the clutch packs up) but it did not have a 4WD-Low setting.

I thought the generally accepted answer was AWD was constantly on and 4WD you had to engage or disengage.

In reply to NickD:

It is but people love splitting hairs. Hell there's 4x4 suvs without a low range and some awd vehicles that have a low range too! So basically selectibility. Awd is constant, 4x4 is selected

chiodos wrote: In reply to NickD: It is but people love splitting hairs. Hell there's 4x4 suvs without a low range and some awd vehicles that have a low range too! So basically selectibility. Awd is constant, 4x4 is selected

Some systems are fulltime 4wd though (90s Land Cruisers, for example). IMO, 4wd has mechanically distinct modes. So it may not be possible to disengage it to 2wd, but if you have low range that's not just an extra low CVT gear, or you can mechanically lock the center diff, it counts as 4WD. If it only operates in one way from a mechanical perspective, it's AWD (which is why the STI doesn't count as 4WD).

If the 2wd version of the vehicle is FWD, it's AWD

If the 2wd version is RWD, it's 4wd.

But the people writing marketing and putting badges on vehicles don't always get it right.

ultraclyde wrote: If the 2wd version of the vehicle is FWD, it's AWD If the 2wd version is RWD, it's 4wd. But the people writing marketing and putting badges on vehicles don't always get it right.

Also, not true. Once again citing the old 4WD Subarus (Not sure if there are others like it, they are pretty weird, I mean, the handbrake works the front calipers for God's sake), they resorted to FWD when the transfer case was disengaged.

Alright. This bugs me.

All that 4x4 means that a car has 4 wheels and all of them are driven, given equal traction. As others have noted, it is usually used in reference to a car that has selective drive modes- 4x2, 4x4 low and 4x4 high. It is a holdover term from when most cars only had two driven wheels. As regular cars began to have all of the wheels driven, somebody decided that another term had to be used.

That leads us to AWD. In vehicles with four wheels, AWD is a form of 4x4. Period, the end. However, AWD could also be 6x6, and so on, provided that all of the wheels are driven. In common usage, most people refer to systems that are always engaged as being AWD, but most people call those neat plastic bricks Legos and facial tissues "Kleenex" as well. Others know what they mean, but it isn't exactly right.

My 4Runner has a dual range transfer case (4hi and 4lo) with a selectable locking center differential. It is regularly an AWD vehicle that can get progressively more suited to bad traction situations by flipping switches and pushing buttons. It is generally considered more capable than my Subaru Forester off-road, but both vehicles are 4x4 and both are also AWD. The 4Runner just has better gearing and more ground clearance. If I dropped a dual range box in my Forester (or just lowered the gearing a whole bunch in general), went with more aggressive lockup in the center and rear differentials, added an LSD or locking front differential and increased the ground clearance a bit, the gap would diminish.