Land Rover Discover: AWD or 4WD?

Got into a discussion on youtube with the guy from Team O'Neal Rally school about wether the Disco is AWD or 4WD. My argument is that while the Transfer case lacks a 2High, it is still a transfer case that needs to be physically interacted with to choose between 4High and 4Low and wether it is locked or open. Part of my definition of a 4WD vehicle is that it uses an actual Transfer case instead of a transmission with a built in output to the rear wheels.

He insists that the Disco is AWD simply because it lacks 2High and the Transfer Case allows front and rear driveshafts to turn at different speeds instead of being locked together all the time.

What is the hive's opinion?

In reply to mad_machine :

I think I lean toward AWD... But then I deleted three paragraphs because I don't think it's a simple either/or these days.

Classically, I put AWD down to anything with a center diff that was driving all wheels all the time, and could do so happily on dry pavement with no adjustments, but helped when things were slick. Subarus for quite a while now. Audi Quattros. Etc.

I put 4WD down like traditional pickup trucks; put it in 4WD (hi or lo), lock the hubs where needed, and you've got fronts and rears turning the same speed, period. No center diff.

But there's a lot of automated or semiautomated stuff these days that blurs the lines. I don't think the transfer case is a good example; doesn't even an E30 325iX use one? Moreover, the fact that your LR (I'm guessing/assuming) can have both an unlocked or locked center diff puts it on both sides (Can you lock the center diff? If not, I'd more firmly say AWD). More like it can be in AWD or 4WD "mode", if those terms mean anything anymore.

Of course, the more confusing it becomes, the less the terms matter, and the more we just have to understand what vehicles do what. There's a running story about my wife finding out years ago that my brother in law's F-250 was "both 2WD and 4WD..."

I always took AWD to apply to any vehicle with a viscous center diff. As in yes, the disco is AWD. I don’t think 2HI has anything to do with it - though without it the average 4WD vehicle would be pretty terrible on the street so maybe it does. 

that is the thing, DC. The transfer case on the Disco is not Viscous. It is all gears like any other 4wd's transfer case. Much like the diff in the front or rear axle, it uses gears when unlocked to transfer power to the axle with the least grip. It's really rather simple and uses no voodoo fluids or electronics to work. It's purely mechanical.

If you have NO OPTION for 2wd then it is AWD.

That feels more like face than opinion but there it is regardless.

The ZJ with the n249 xfer case works the same way as the disco albeit through a VC, and I've always heard them described as AWD. There's a guy in FL somewhere competing successfully in an AWD class with a ZJ like mine.

EDIT: thought to add - the np249 transfer cases use a viscous coupling and you had choices of 4Hi (full time 4wd or AWD), N, and 4Lo (gear reduction, locked 50/50 drive through xfer case). The optional np242 had 2hi, N, 4hi, and 4Lo but used a planetary gear system to still variable split f/r in 4hi for AWD on the road. So some of them were very similar to the Disco setup.

When a transfer case is unlocked there is some kind of clutch or slip mechanism or fluid making it AWD or there is a 2WD setting.  If there was not it would hop and squeal on dry roads like a spool in the rear of a car.  You have both AWD (unlocked transfer-case) and 4WD (locked), a lot of vehicles do not have the option and that is why they are called AWD. 

Most cute utes and AWD cars have no lockable center diff that makes them AWD.  My truck has an auto mode on top of 2WD, 4WD and 4 low.  In auto mode it just determines when to lock or unlock the center diff, if may even do so variably with an increasing % heading to the front as needed.

What about Jeeps quadratrac system, it was full time 4WD with no 2WD option.  It had a lockable clutch in the transfer-case for locked 4WD, so it was really also both AWD and 4WD long before AWD was a thing (1970's). 

Dad's old Dodge Snow Commander was what they called full time 4WD back in the day, same deal a transfer-case with 4, 4loc, 4low and 4low loc.  It was really AWD by todays terminology, so that's what it really is just a change in terminology to sell cars. 

I just fell down the rabbit hole reading about 1st gen Discoveries. And you’re right of course the transfer case has no fluid coupling it’s a gear diff just like a front or rear diff. Somehow I had it in my head from my OG Range Rover days that there was a fluid diff but that came later in the Range Rovers. 

No 2wd would make me lean toward AWD because that is it's natural state and it has a center diff. 

So these have an open but fully geared center differential, that is lockable, the newer models that have a variable unit.  

http://exploringnh.com/content.php?71-Which-4wd-System-Does-Your-land-Rover-Have

So yes it is AWD with one axle able to spin faster than the other for turning on pavement or getting stuck.  But you can call it 4WD if you want to and not be wrong.  

I would call it 4WD, due to the geared nature of it VS some variable locking device or clutch or viscous fluid.  Truly only 4WD if it has the front, rear, and center diff locked.  With the center locked you can still have one front and one rear wheel free spinning.

I thought my KJ service manual might give some insight, but no.  It just covers the two transfer case, one direct (4wd) an one with a viscous coupling (awd).   The 4wd has 2wd option, didn't think to check if the awd does..  

So you guys would call a RR Classic AWD because there's no 2wd option?

What would you call an NP242 with full time 4wd as well as part time 4hi and 4lo?

In reply to buzzboy :

It has an option for 2HI therefore it’s not AWD all the time. You can use AWD when needed however. Just like my Sierra 1500.

”I didn’t use 4x4 this storm, I just put it in AWD”

In reply to buzzboy :

The sticker pictures I would call everything drive, 4PT is what we call AWD now, 4FT is what I call 4WD.  So all 4WD trucks that have 4PT are also AWD, If a truck doesn't have 4PT then it is a 4WD.  

This is fun.

There are many AWD systems now, but for me to call something 4WD it needs to have a full mechanical locked center differential option.  Anything else is AWD or electronic brake actuated wizardry. 

My Nissan has all of the above, it has 2WD, electronic AUTO mode that adjusts the center diff as needed, 4WD with the center diff locked, and 4LO. The latter also engaging the electronic traction control where it applies the brakes to the tires that are off the ground sending traction to the tires with traction.    

Four wheel drive system with differential in transfer case is AWD (All wheel drive). Can be driven in all road conditions. Also called full time. 

Four wheel drive system without differential in transfer case is 4WD (Four wheel drive, also called part time four wheel drive). Can only be driven in slippery terrain, or drivetrain bind/breakage may occur.

My 99 jeep cherokee with the np 242 therefore has AWD and 4wd positions in transfer case. Full time and part time.

Used them plenty this past weekend at the local ohv park.

The discovery is AWD if the transfer case differential can not be locked. 

AWD and 4x4 are just American designations.  When I grew up, if it had the ability to send drive to all four wheels, it was a 4x4.  Simple as that.  Land Rover's tag line for a long time was 'The best 4x4 by far'.

If we're going by arbitrary made up definitions though, I always thought the decider in this country was if drive could be sent to all four wheels with no input from the driver it was AWD.  If the driver had to do anything from pressing a button up to engaging the transfer case manually then getting out and locking the hubs, then it was a 4x4.

This sounds like a case of someone wanting to belittle a 'furrin car.

In reply to NoBrakesRacing :

2003 and late 2002 can't be locked.. everything before and after can. I am on the hunt for a locking T-case for my disco.

ebonyandivory said:

If you have NO OPTION for 2wd then it is AWD.

That feels more like face than opinion but there it is regardless.

that seems kind of strange though because then you have things like the 4Runner V8 that is full time 4 wheel drive th but basically uses atypical transfer case setup. I don't think I've ever heard anyone refer to a body-on-frame truck like the 4Runner as all wheel drive. In fact it has badges all over it that say 4WD

The 4 Runner example is why I think the whole AWD Vs 4x4 is just a dick swinging argument for people desperate to make a pointless point.