D4 rear diff lock

[Dr LC8]

Hi all,

Good morning. I am new here...and I thought you guys are the most informed and educated on D4 aftermarket.

I am based in UK. I own a D4 2012 SDV6 256bhp. I don't have the factory active locking differential and I would like to fit one.

After extensive research I found this for sale

Manuelle 100-%-Sperre, Hinterachse - Discovery 3 und 4

by the respectable https://www.matzker.de

I wrote to them enquiring it this was compatible with my car and they said yes.

Do you actually agree? What do you know about it? I thought this product was available for D3 but not for D4.

Thanks for your help,

Nic

[Graeme]

If you can advise how to change the site to English then I may be able to help.

[sheerluck]

Interesting. It says in the description that it's made by ARB, ARB certainly don't list a rear locker for a D4 on their website, only the D3 as you mentioned.

[sheerluck]

Didn't you do German at school Graeme? :D

[Graeme]

Only French and Latin in my days.

[Graeme]

ARB initially thought their rear locker fitted the D4 as well as the D3 but then discovered that it didn't fit the D4.

Retro-fitting an e-diff is possible and wouldn't need calibrating if the control module and e-diff came from the same vehicle.

[Dr LC8]

Thanks Guys,

I was hoping that ARB updated its rear diff lock.
I used google translator and then I wrote to them. In all fairness they also said that it can be fitted to my car but they have never fitted one:confused:

I should enquire ARB directly...

Nic

[Dr LC8]

Retro-fitting an e-diff is possible and wouldn't need calibrating if the control module and e-diff came from the same vehicle.

Graeme can you please explain this a bit better?:confused:
I have been reading about it here and there but I am not sure how feasible it is.
In the sense that here in UK very few D4 are fitted with this factory optional. Riding one will be extremely difficult. And who is going to fit it. Can that be fitted without coupling with TR? Thais would be a much easier option.

Many thanks
Nic

[Graeme]

I understand that the centre can be made to fit with a slight modification to the diff housing opening.

[Dr LC8]

Look at this:

https://www.ebay.co.uk/itm/231999645510


Can I get someone to fit it??? It should go in straightaway. The issue is the connection with TR and ETC. I guess I can control it with a switch.

Nic

[Graeme]

Does the e-diff have the same ratio as your vehicle, ie is your's an 8-speed?

The drive-shafts have heavier duty CVs to better survive the torque and you would need a control unit, preferably the one from the same vehicle, and the wiring harness from the locking motor to the control unit on the LHS and the connector and wiring to where the control unit connects to the main harness nearby. Once fitted the e-diff has to be enabled using specialised diagnostic equipment then also calibrated if not using the e-diff control unit from the same vehicle.

Edit: Corrected wiring description.

[Dr LC8]

Does the e-diff have the same ratio as your vehicle, ie is your's an 8-speed?


Thanks Graeme.
Yes it is the same ratio, mine is an 8-speed car.

In essence what you are describing has been done by a guy...apparently successfully

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

However what scary me is the electronic side of things. Not only because it will require a hell of a job in terms of time but also because the risks of failure will be high.

I am wondering if the original diff lock (the one on ebay) can be fitted and activated manually with a switch independently from the Terrain response and ETC systems. What you recon?

Nic

[Graeme]

The e-diff has a stepper motor that the ecu operates in a forward and revere direction to increase and decrease pressure on clutch plates. Hence a simple on-off switch isn't suitable.

[Dr LC8]

The e-diff has a stepper motor that the ecu operates in a forward and revere direction to increase and decrease pressure on clutch plates. Hence a simple on-off switch isn't suitable.

You mean it doesn't work as a traditional diff lock with a spindle to block? So you either connect it to the ECU or nothing?

And how difficult do you recon it is to connect it? Would you think that it is a reliable solution? Cost effective?

Nic

[Disco-tastic]

No it uses clutch packs to share load infinitely between the two axles.

Once you have it installed and operating on your car, i see no reason why it would be any less reliable than if it were factory installed. (Excepting the condition of the installed diff)

I have wanted to do this to my car, though cost (and necessity to some degree) has stopped me. In my opinion it is a better solution that an aftermarket locker like ARB, as it integrates with the traction control.

Whatever you do, please let us know and post plenty of pics :)

Cheers

Dan

[Babs]

So how does the factory E-Lock work, is there a switch/button to push or is it all automatically done through terrain response system. So you have no option to turn on when you want❓

Sent from my iPhone using Forum Runner

[Disco-tastic]

Yep all automatic. No user control.

Its the same as the centre diff lock in your D3/4. The computers control all of that for you - i do sometimes find that frustrating, as being able to lock the centre diff manually would save some wheel spinning and brake wear :p

Cheers

Dan

[Graeme]

More importantly, being able to lock the centre diff would allow drive with a broken front or rear CV, which as it stands is only possible in basically a straight line in rock crawl.

[Babs]

More importantly, being able to lock the centre diff would allow drive with a broken front or rear CV, which as it stands is only possible in basically a straight line in rock crawl.

Good point, there is no way around this in an emergency ❓

Sent from my iPhone using Forum Runner

[Graeme]

I have a plan that I would try in an emergency, that requires a switch to be fitted in the main power or earth wire to the TC motor that would be switched off once rolling in rock crawl. The diff is only locked once moving and only before either an actual or perhaps calculated high oil temperature is reached. The locking mechanism is reportedly not designed to be engaged for extended use but I would give it a go if stranded in a remote location, noting that a change to high range would not be possible with the motor disabled as the same motor does the range change.

[hv_man]

I remember reading the CV's are different (higher rated) on the e diff D4s.
Perhaps ask if the CV's and shafts can also be supplied with the e diff not sure what other parts are different

I spent sometime looking into the locker options last month before I purchased my D4. After talking to a ARB and other diff locker suppliers no solution is available and none in development. Also spoke with a number of LR specialist workshops around the country again no luck. for D3 yes but no D4

[Dr LC8]

I agree that ideally you should use the original the way it was designed to work or alternatively a proper aftermarket solution like ARB...which unfortunately doesn't exist.

I have the guys at ProSpeed (http://www.prospeed.co.uk) looking into it for me. However there is very little experience on this.

I believe that one of the owner at MUDTECH 4?4 | Discovery 3 & 4 special parts (http://www.mudtech4x4.com) did it on his D4 but I didn't manage to talk to him as yet.

The guys at Matzker KFZ Technik (http://www.matzker.de) never installed a rear diff lock to any of their Disco.


On the other note I agree with the beauty of the old system you mentioned above.

My Disco 2 was in fact perfect: it had Traction Control and a manual centre diff lock. If the electronic was to play up or a CV gone it would have still work...
I think the Disco 2 is a good 4x4 with good mix of modern (air suspension, ETC DHC) and all mechanic solutions...but you can't have everything...:mad:

Nic

[Dr LC8]

I spent sometime looking into the locker options last month before I purchased my D4. After talking to a ARB and other diff locker suppliers no solution is available and none in development. Also spoke with a number of LR specialist workshops around the country again no luck. for D3 yes but no D4

This is a bad news:( None in development!
I must admit with insight I should have looked for one with a rear lock when I bought mine. But here in UK they are very rear.

I was upsetting going off roading last weekend with a friend. He has a D4 with no rear lock but he has big 275/65 Cooper STT on 18 wheels. I have Cooper A/T Zeon LTZ. Both of us got stuck on the same wet rocky/muddy step. I could clearly see one single wheel spinning on rear and front axel! So Traction control was working up to a certain degree. We eventually negotiated it working on ground solutions...

N

[BobD]

Did you have them in low range rock crawl?

[Graeme]

Even just more and constant go-pedal should have made TC work properly to do the job. I've been paddling through sloppy stuff on my road (not driveway) in grass/gravel/sand mode so can see that the centre diff doesn't normally lock yet TC is chattering away.

[Grentarc]

Even just more and constant go-pedal should have made TC work properly to do the job.

Others have also found that traction control does not work if you have a foot on the brake pedal too.

[Disco-tastic]

Others have also found that traction control does not work if you have a foot on the brake pedal too.

I found that out last weekend...

Wiggling the steering wheel with a constant throttle application seems to work well too.

Cheers

Dan

[Dr LC8]

Did you have them in low range rock crawl?


Indeed!

[Dr LC8]

All of the above done. Even disconnect the ETC...


Nic

[Meken]

All of the above done. Even disconnect the ETC...


Nic


What's the esc? There will be some things that will stop a D4 - but you will get some wheel spin before the terrain response system works out what to do and as others have said a slight increase in power to increase the wheel spin works to make the tr system activate more

[Dr LC8]

ETC: Electronic Traction Control