Locking Diff question PLEASE

I am an new L3 owner and absolutely love this vehicle and have a recent issue with the my rear locking differential. I have the HD option and was wondering if someone could please explain in detail as I have a technical and electrical and mechanical aptitude. What is happening from the computer ABS module to the Diff ECU, feedback from the stepper motor and Differential locking mechanism. How the heck does this all operate ? does it matter what mode of terrain your in and our is the locking diff always in operation? so curious.....? someone please provide me with this knowledge

I'm not an expert on the locking rear diff, but I do have one. My understanding is that it is not "turned on" until you use one of the terrain response settings, which then preloads it. It is a locking variable diff, so it's not engaged or disengaged per-se. However rock crawling mode will lock the rear diff I believe. The big difference from most locking diff sis that it is variable as compared to a typical air locker. Hope that helps!


Every Day is a Good Day Surfing...Some are just Better Than Others

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Not sure how all the electronics work but if you select the 4x4 screen, you can see the lock symbol change from unlocked to locked when it engages.

If you want a good explanation of the theory that went into the terrain system design and when each mode should be used, look at the Terrain Response White Paper. Since I can't seem to post links here, just go to Nathan Wood's website:

w w w . lr3 tips. wordpress. com /owners-manuals/

and scroll down to the bottom of the page. Click on the “Terrain_Response, An Innovative Integrated Traction System for the Land Rover Vehicles” link.

I don't believe it's quite accurate that it's never locked in General mode or that it's always locked in Rock Crawl. I believe there is a torque threshold above which it will lock. In General mode and Rock crawl that threshold is high and low, respectively.

Houm_WA said:

I don't believe it's quite accurate that it's never locked in General mode or that it's always locked in Rock Crawl. I believe there is a torque threshold above which it will lock. In General mode and Rock crawl that threshold is high and low, respectively.

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I would not be surprised at all if the rear differential will NOT lock at all while in "high range". By "general "mode I assume you mean the terrain response being set to "none" for specific terrain surface.

There is no situation I can think of where anyone should even wish for the rear diff to lock while in high range gearing. The center maybe, but not the rear.

Yes, General was a reference to no special programs selected. Agree on what you've stated and for the most part in General, nothing locks, high or low...but that doesn't mean it can't.

Likewise, in Rock Crawl, the rear locker is a lot more sensitive and locked a lot more often but I've certainly looked down and seen it open on the 4x4 display. Heck, other times I've seen the rear locked and the center open! It's entertaining for me to watch what the LR3 is doing. Sometimes it's surprising.

One thing I hardly ever experience: Traction Control.

Thank you very much this was the exact detail I was wanting. It is evident in some of the responses to my question that most people have no idea what's involved in this 4 x 4 terrain response system. Their should be a test before you buy one of these to understand these features as this its the heart of how this Rover operatrs and why it is such a great off road beast.

Pardon me,

I read through the replies and I don't see any bad info here?

Houm_WA said:

One thing I hardly ever experience: Traction Control.

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The traction control on this truck is absolutely amazing. I took mine (w/locker) to an offroad park with an FJ60 and a bunch of Jeeps. We spent the day doing a variety of obstacles from climbing and descending hills that I couldn't have walked up/down to fording rivers, mud pits, etc. There was an obstacle or two that I couldn't do because of my ground clearance and/or approach angles (only the jeeps with 33+ and 4" of lift could do them), but at the end of the day, I was able to do 95% of everything and come out with a relatively clean truck. The jeeps (and I'm not jeep bashing by any means... I have nothing against them) were completely covered in mud and the ones who started with no top either had mud covering the inside of their trucks or had to put their top on. I had barely any splatters and the ones I had were just on the sides of the car directly behind the wheels.

This is all due to the different philosophy of driving. The jeeps simply spun and spun the wheels, flinging mud everywhere, but eventually getting through. The LR3 almost danced through each obstacle... rarely spinning a wheel, but always finding the traction necessary.