Active Rear Locking Differential: is it worth? Rational?

[Dr LC8]

Hi,

I have a LR4 2012 SVD6 256 HP 8 speed UK Model.
It came with central diff but not rear. It was a second hand car and I didn't have the chance to add it on.

I have done an extensive research and it can't be installed as aftermarket. There is a company in Italy/Germany (Mudtech4x4) who is studying the option of retrofit one. In case I even found one:p.
I am loosing sleep on it (obviously for no reason;))

Is it worth? On three separate of occasions I got stuck and I thought that with a read lock this probably wouldn't have happened. On the snow, on soft sand, on wet rock climbing (a mayor step to take). While I agree that the TC is extremely capable I still think that two parallel wheels spinning together in extreme situations (as above) will work better. TC, even when off, won't give that boost that you need to overtake certain obstacle or tricky terrains.

Am I wrong?

There is no doubts that in Australia you have more experience in using LR4 off road. Please educate me!

Nic

[Nicky]

Better in tight rough stuff and better re-sale value

[Disco-tastic]

While the rear locker definitely adds capability for most situations (particularly sand and even snow) my guess is your tyre pattern, profile and pressure will have more effect on your available traction than a rear diff lock.

What tyre size and pressures are you running in sand and snow?

For the rock step or scrabbly incline the rear diff lock is definitely an advantage, but versions without will go almost as far as those with.

Cheers

Dan

[Dr LC8]

While the rear locker definitely adds capability for most situations (particularly sand and even snow) my guess is your tyre pattern, profile and pressure will have more effect on your available traction than a rear diff lock.

What tyre size and pressures are you running in sand and snow?

For the rock step or scrabbly incline the rear diff lock is definitely an advantage, but versions without will go almost as far as those with.

Cheers

Dan

Dan You have a point. However, generally speaking you compare cars with same tyres and wheels.

I run 255/55 19 Cooper Zeon LTZ on standard pressure. In snow I use Vredestein Wintrac Xtreme same size and pressure.

However when I got stuck on the wet rock climbing, my mate was on the same car but with much better tyres: Cooper STT Pro 275/65 18 on Compomotive wheels. He got stuck the same. On the rear axle one wheel was spinning the other was blocked :confused:!

N

[Tombie]

If your tyre pressures were full pressure then I am not surprised you struggled on wet rock...

[Tote]

My experience with my D3 was that a rear diff lock would only get you %% further than without. What it did do was make the other 95 % of situations much easier.
Would I fret about not having one if I already owned a vehicle without one fitted? No
Would I order one with a new vehicle or make it a significant requirement for a second hand one ? Absolutely.

Have a look at this video:
https://www.youtube.com/watch?v=GECmf0B-vT0

The Black RRS does not have a rear diff lock and on the day it was obvious that the diff lock equipped cars did things just that bit easier. For comparison my vehicle was the Atacama Sand D3 with the tyre on the roof.



Regards,
Tote

[Disco-tastic]

Dan You have a point. However, generally speaking you compare cars with same tyres and wheels.

I run 255/55 19 Cooper Zeon LTZ on standard pressure. In snow I use Vredestein Wintrac Xtreme same size and pressure.

However when I got stuck on the wet rock climbing, my mate was on the same car but with much better tyres: Cooper STT Pro 275/65 18 on Compomotive wheels. He got stuck the same. On the rear axle one wheel was spinning the other was blocked :confused:!

N

Hey Dr LC8.

Here's a thread about tyre pressures and rear diff locks :BigThumb:

http://www.aulro.com/afvb/l319-discovery-3-4/237440-hill-climb-comparison.html

As said it definitely helps, but the lack of it shouldn't stop you in most situations.

Hope that info helps you make the call :)

Cheers

Dan

[Disco-tastic]

Also the RRS in Tote's video is from memory a 2005 model. The Terrain Response and Traction Control has come along way in 10 years and is much better, closing the gap to eDiff equipped vehicles.

[Graeme]

I have done an extensive research and it can't be installed as aftermarket.Your research has not been sufficiently extensive as it's quite simple to retrofit, with the biggest hurdle finding a complete rear diff with the correct ratio supplied with at least the connectors with wire stubs although wiring right through to the RDCU would best. However the D4 e-diff driveshafts with their stronger CVs should also be fitted.

I have just the diff itself left to fit to my MY12 L322, with the control unit fitted, wired and enabled in the CCF. As the RDCU came from a different vehicle to the diff, the diff will have to be calibrated to the RDCU.

[rocket rod]

If your tyre pressures were full pressure then I am not surprised you struggled on wet rock...

x2. Lower pressure is the best way to increase traction. If you haven't tried it, do a test in the garage on level floor. Measure the tread contact area on the floor at full pressure, the air down say 10psi and measure again, then do another 10psi and measure again. The tread contact area will increase enormously. Just make sure you slow down with lower tyre pressure. Here's a vid showing the effect on the beach but it applicable to rocks as well.
https://www.youtube.com/watch?v=X75zqoaWhjU

[Redback]

ARB do a front and rear air locker for the D3/D4

[Graeme]

IIRC ARB have withdrawn the D4 rear locker.

[TuffRR]

No ARB rear locker for D4. Everytime i ask them, they say no demand and that i'm the first person to ask. I've asked a few times over the years from a couple of different stores so their counting is not quite right.

Mine doesn't have a rear locker, i wish it did but i'm probably in the minority of people who push these things to the point that it would be frequently beneficial. If one became available (preferably retro-fit LR) i would be all over it.

[winaje]

A retrofit of the OEM e-diff can be done and has been done. But it would take time, cash and skill.

DISCO3.CO.UK - View topic - Rear lock diff retrofit for D3 and D4 (http://www.disco3.co.uk/forum/topic94012-15.html'sid=677c1ccfe36c020a7651705d6894ab57)

DISCO3.CO.UK - View topic - Rear locking differential (http://www.disco3.co.uk/forum/topic52473.html)

They link to us, so I see no issue linking to them...

[AnD3rew]

I would also ask if you were stuck if you are sure you were in rock crawl mode. It is amazing how much difference it can make. I was all ready to winch myself out of a tough rocky steep incline one day after trying everything I could think of short of that when I decided to have one last go and realized I was still in grass, gravel snow mode. Put it in rock crawl and it just walked out no sweat at all.

Unless you frequently push the car to the extremes I would go tyres and pressures first before the complexity of trying to retrofit the e diff. Next would be an ARB locker.

If I was buying new now I would specify the e-diff, just because I could, not because I have experienced a real need for it, I have gone some pretty amazing places without one.

[Bytemrk]

If I was buying new, I'd definitely order a locker as they are such a small addition to the total price.

However, there are many many D4's running around Australia that get very serious off road that do not have one.

Gordon from GOE told me he felt that in the later vehicles, the traction control had got that good there was less and less reason for an e-diff being a needed item.

As the others had mentioned, tire pressures and terrain response mode choice are likely to have a lot more to do with how far you will get on wet rock.

[Tombie]

Mark..... Tire? You going all Yankee on us

[fitzy]

What's with all the wheel lifting in the video?

[Bytemrk]

Mark..... Tire? You going all Yankee on us


Ha Ha .. lol.. nope just tired on you :p :D

[Tote]

What's with all the wheel lifting in the video?

D3s don't need all the wheels on the ground to progress..... they kind of do that naturally off road, it makes for good footage if they have a few wheels in the air though, and there may have been some playing up for the camera involved.

Regards,
Tote

[SBD4]

Definitely check you have selected rock crawl, DSC OFF and on 255 55 19 pressures no lower than 30PSI unless on sand.