Rear locking differential

[nwoods]

I get it. I'm saying I have seen numerous vehicles show locked, that are not equipped with a rear locker. I think the sensor system that detects when it would trigger the locker is integrated into the car, and so it works, it just has nowhere to send the signal to.

 

[Houm_WA]

...that's quite a teaser; so it's basically telling the driver "your rear diff would be locking right now if it could!"

As for it being more of a limited slip; I say "no." It may engage in a similar fashion. It has a pre-set torque threshold that tells the ECU when to lock, and depending on the mode it gets locked in pretty quickly too. When it engages, it stays locked for longer than you would think. The way I understand a limited slip working is that it only transfers torque after you have started spinning your wheels and probably lost your momentum. It also may not be necessarily delivering equal torque to each wheel the way a locked diff does.

So, I say no it's not a limited slip, it is exactly what it says it is...an infinitely variable electronically-locking differential.

 

[Boaz]

If the screen showed that it was locked when it wasn't, that would be a malfunction. That would be like the HDC icon being lit when you switch into Rock Crawl, but HDC isn't really on. Talk about dangerous. My only experience is with my old unlocked Sport (06). Even on the most extreme rock crawl steep stuff, it never showed the rear icon as locked.

 

[umbertob]

The rear locking differential - if the car is fitted with one - is controlled by its own separate electronic module, connected to the transfer box control module as a ***** unit. This is the module that causes the padlock icon to change from green to red on the 4x4 screen, reflecting the actual status of the differential back there. If you have an open differential, you don't have this module. Whether the rear lockers padlock symbol on the display remains green all the time or changes to red whenever the center differential engages, who knows for sure at this point. It could in theory turn red, if the connections for the missing rear diff module were bridged on the transfer case control module of a car without rear lockers. Or it could stay green all the time. There's probably a tiny $0.10 jumper on a circuit board somewhere making all the difference...

When I went to one of those local Land Rover Experience promo events a couple of years ago I drove a "borrowed" Sport on the short demo course (it was inside a soccer stadium, leftover course from the X-Games, pretty cool!) If anyone has been at one of these, all cars are set to show 4x4 Info on the touchscreen during the course. When I went through a steep, sandy off-camber hill on the course, I noticed that both differential symbols on the monitor turned red, so I asked the guy dressed like Indiana Jones sitting next to me if the car I was driving was fitted with rear lockers, like mine. "No, all cars on the course are fitted with stock tires, no rear lockers. We need to show our guests what these babies can do with no options." "Why did the rear padlock symbol turn red just now?" "Because they both turn red on the display when the center differential locks. It's just the way the User Interface works if you don't have LRD." Maybe they think RRS drivers are dumber? Or maybe Indiana Jones didn't know what he was talking about. My RRS has rear lockers so I will never be able to prove or disprove the theory.

 

[nwoods]

For the record, I was NOT the Indiana Jones in question in Umberto's post above, but my numerous expereinces in unlocked RRS/LR3's is similar.

 

[Boaz]

"Why did the rear padlock symbol turn red just now?" "Because they both turn red on the display when the center differential locks. It's just the way the User Interface works if you don't have LRD." Maybe they think RRS drivers are dumber? Or maybe Indiana Jones didn't know what he was talking about.

How about C - All of the above?

My current LR3 does have the heavy duty package, and I notice on the screen that sometimes only the center diff is locked and other times, both are locked when off road. So they don't both turn red on the display when only the center is locked. My experience in my old unlocked Sport was the same. They don't switch the icons on the 4x4 screen together all the time. Maybe there are some malfunctioning ones out there though, and that is just the BS explanation they gave so they wouldn't have to admit something was wrong and fix it.

 

[umbertob]

Gee Scott, I think you just called me dumb?

 

[zbysiu23]

How big of an advantage is to have the locking diff vs not having it.. is there anybody who could testify having driven both...without the TC there was a whole world of a difference....I am just trying to make myself feel better since I do not have one..

 

[Boaz]

Gee Scott, I think you just called me dumb?

No, but they think we are. C'mon Umberto. You know how loved you are around here...

 

[nwoods]

How big of an advantage is to have the locking diff vs not having it.. is there anybody who could testify having driven both...without the TC there was a whole world of a difference....I am just trying to make myself feel better since I do not have one..

Slim to none. TC is that good. Basically in my experience, the rear locker makes things easier, but they are still doable without.