Hmmm... 50% "locked" is not "locked." What does that mean? 50% of what is going where? Locked means "the right wheel is mechanically pinned to the left wheel by means of a device that eliminates the differential for all practical purposes and just "welds" the two sides together. Now if LR can fully replicate that with electronical wizardry then I'm fine with that -- all I want is for power to always be going to the tractive side of the driveline (l/r or front/rear), The old way works very well, of course. I'm hoping the Dfdr works just as well, whatever means they utilize.

 

Yes, the LR can fully replicate locked (the two sides welded together). That's what I mean by a 50/50 split. Each axle turns exactly the same, no matter what. It's a torque split, 50% going to each side. An open diff with one wheel spinning (like if it's in the air) and the other stationary would be a 100/0 split. I might not have the terminology correct but it's how I think of things.

The Defender has limited slip differentials. They can act like open differentials in normal driving. The can be completely locked (welded together). They can also be somewhere in between. They are hard to describe in a few sentences. Instead of a metal sleeve that locks into position (it's either locked or not), they have clutch packs. By varying the amount of pressure on the left and right clutch packs, power can be distributed 70/30. Here's a good video that describes the basic principles. It will do a much better job describing them than I can.

 

The Motortrend article I linked to above states ""the Defender's two diffs are capable of acting as both limited-slip and locking-differentials." They are LSD but they can also lock. I don't know how they lock, perhaps they have both clutch packs and the sleeve.

Do you have a link to that review? I'd like to see what they have to say. Most articles I've read praise the Defender's off road ability, and these diffs are a big part of it.

 

Okay, I can accept your terminology (though I don't think it's "standard") now that you've explained it. Thank you.

But if so, what you're calling "50% or 50/50" is the equivalent of "fully locked." It's not partially locked. That's what I'm not getting. If it's "partially locked" that's what's known as "unlocked." Traditionally, off-roaders with LSD and off-roaders with open diffs are known as "unlocked" or "without lockers", something like that. "Locked" has always been a digital term -- it's either locked or its not, and if it's 1% unlocked it's unlocked. So I'm still unclear on what LR is meaning when their icon shows a diff to be "partially locked?"

 

Agreed. I specifically looked for off-road-centric publications or web reviews because I figured they will have a lot of experience with modified, highly capable, traditional off road vehicles, which is what I have experience with, and I wanted to see how they compare this Defender to the capabilities of the traditional one. Most of the outlets like R&T, MT, C&D, etc. are road-centric and demand a lot less of their off-roading vehicles. As such they do a great job of representing the majority of buyers, even those who actually take their LR or Jeep or Toyota off-road regularly. And they've all been unanimous in praising the Defender, but for many complaints about twitchy/jumpy brake pedal, which I certainly noticed in test drives.

FourWheeler magazine shootout, Defender part.

 

Let me take a stab.

If you think of it so binary, that is having two states locked or unlocked, then yes it's easy to see how anything between is confusing the issue.

I would say that LSD is NOT unlocked (completely open), because it does "Lock" once a certain amount of slip occurs. One only has to many a sharp turn in the rain with my Jeep's Trac-Lok rear to feel the result. But to some extent that's another conversation.

Most AWD vehicles today use some form of variable couplings in the driveline to allow for wheel speed differentiation while also powering some to all wheels at a time.

How that is managed is often through clutch packs which can open enough to slip some. That's how you get torque splits like 70/30 front to rear, or sometimes side-to-side.

The weakness of those systems (as recently illustrated by journalists hooning Bronco Sports off-road) is that when push comes to shove and two or three wheels are unloaded (uneven hill climb) you risk so much slip that you start to overheat these clutch packs and the powertrain control module may shut it down to prevent damage.

Now we're told the Defender has two variable locking couplings (center and rear) and without verifying I've bought one lol. The question is do they truly have the ability to lock, prevent slip, and therefore push through the tuff stuff without damage? I certainly hope so and have not seen anything in early tests or reviews that has made me doubt they can actually lock.

I just don't yet know how they go about it mechanically.

 

I agree, "partially locked" is a confusing term. I think what they mean is that it is in limited slip mode at that point. It's not unlocked, it's not locked, it's limiting the speed difference, left to right, to some degree. The icon shows the amount it's limiting this, from not limiting it at all (e.g. open diff, one wheel could be stopped while the other is spinning), to limiting it somewhat, to completely eliminating all difference between left and right (e.g. fully locked). Somehow they equate this with "partially locked."

 

As well as clutched differentials, Land Rover and their (mostly German) suppliers also have become skilled in the use of the fast, differential braking technology and more than 20 years of steady evolution in the sensors / control logic and the hardware to master this capability.

JLR has been evolving this capability in all their products since the start of the first Discovery and continuing through the Evoque and their other products and into the new Defender.

I, for one, purchased the new Defender primarily for this refined capability -- for use mostly off-road (but not far from civilization --- and a JLR computer). In this situation, which occurs very often when we consider the 4x4 as a working tool versus as a recreational one, I hold the opinion that the New Defender makes other off-road approaches obsolete -- excepting in the case of use in areas where ultimate, remote survivability is paramount (far away from civilization).

The point being raised regarding the robustness of on-off lockers vs. the new technology is an interesting one. I suppose the point is one more to add to that long list of design characteristics already discussed over the past twenty five years which compare capability and usability versus survivability.

 

Three wheels unloaded? Now that's something I'd like to see! I don't know how you'd manage that!

Many years ago (decades, actually), I had two wheels unloaded. The left front was in the air. The right rear barely touched the ground, but didn't have enough weight on it to do anything. I didn't have a rear locker at the time, and this was decades before the electronic nannies we have today were available. I wasn't going anywhere. I had my buddy stand on the right side of the rear bumper. That put enough weight on that tire that I could move a few inches. That was enough to get more load on that tire and get me unstuck.

 

That's a good trick. If you're solo, you can use your 48" HiLift to force one wheel higher and the other one down onto the ground, then drive off the jack. But that's a lot trickier than having a buddy stand on the running board or sit on the hood. I only had to drive off of a Hi Lift once and it's not something I'd want to repeat regularly.