Locker behavior questions

greiswig

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I'm used to having a manually-activated locking differential. So forgive me for some dumb questions.

  1. Which of the "terrain response" settings utilize the locking rear differential?
  2. Does the locking differential just stay engaged in those settings, or does it just look for wheel spin and activate accordingly?
Reason I ask is that there are a lot of places (e.g. slickrock) that really do better with an open differential. In fact, locking the differential in those situations can cause a lot of stress on the driveline. I'd like to avoid that if possible by knowing how best to use the system.
 

Quijote

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I'll start mentioning that when I read the thread title I thought it would be a rant about old naked people at the gym locker room.:biggrin:

Anyway, I am far from an expert on this, but I will say that the locking rear diff comes on far more often than you'd think. Accelerate hard from a stop on a warm summer day under normal mode and the rear diff will lock up here and there.
 

CRYA

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Interested too, but I think from my previous experience there are one or two modes where it was locked full-time, at least in my FFRR. Also, I think the owner's manual probably describes each mode. Failing that, there's one way to find out! Run it through all the modes and see when/how your locker light comes on!
 
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My experience is Sand, Mud, and Rock all engage the locker more quickly than others, sand being the most aggressive. Rock crawl dampens the throttle, brakes, and puts the traction control into hyper sensitive mode and in the lead... it wants to crrrrrrrrrrawl. Mud let’s them slip and spin more (disable DSC for even more fun) and sand is an acceleration friendly setting still vigilantly watching for slipping.

just know, that if the wheels don’t slip, the system doesn’t know what’s going on. It’s a fantastic system. Steady throttle in the right mode will get you through almost anything you can roll over or through. Let the LR do it. (Hardest part!)
 
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BriComp

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At the LR Owners Day they mentioned the traction control doesn't fully engage until 2000+ RPMs so keep that in mind too regardless of the mode.

Sent from my Pixel 4 XL using Tapatalk
 
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morrisdl

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Traction control is a microprocessor controlled 'fight' between engine and brakes.
Makes sense that it requires 2000 rpm and a minimum amount of detectable wheel spin.
This is exactly why I prefer the ARB air locker.
 

greiswig

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Traction control is a microprocessor controlled 'fight' between engine and brakes.
Makes sense that it requires 2000 rpm and a minimum amount of detectable wheel spin.
This is exactly why I prefer the ARB air locker.

2000RPM does seem excessive in most cases, but then I'm not really sure. I have to assume that they did some homework on that choice, and when coupled with the accelerator curves they've chosen, it was the better choice.

I do prefer a locker in the rear axle. I have the stock locker in the rear, which seems to work quite well. In my experience, I have only rarely needed a locker in the front on trails if there is also a center differential; when you're trying to go up and over something, most of the weight is in the back anyway, and some smart driving keeps you going. In fact, on my Unimog, I changed it from a switch that basically applied both front and rear lockers at the same time to one that applied only the rear locker in one position, and added the front if need be (never did, but that thing had insane axle travel) because of the steering benefits of not having the front axle locked.

With my other main trail rig ('90 Isuzu Amigo with Toyota transmission and twin transfer cases), I'd put a limited slip in front and ARB in the rear, which was also great. On trails like the Rubicon or Moab, the most useful setup for the vast majority of the time there was open rear dif, medium low range transfer case in 2WD, with the front hubs not engaged. You can drive slowly and not bind up the steering or the driveline in that setup. Theoretically, our LR4s ought to be able to do that pretty well.
 
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