Discovery 3 e-diff

[GlennS]

I am going to buy a Disco 3 TDV6 & will go off-road. Is it preferrable that the car be fitted with the e-diff or does it not matter ? Any information would be appreciated.

Cheers,
Glenn.

[~Rich~]

Traction control will assist Off Road progress greatly, it's just even easier with an eDiff.
On the second hand market I guess you have to make choices. What do I really want and whats about!

[WhiteD3]

I didn't have an e-diff in the D3 but I do in the D4. To be honest I've noticed no diff (pardon the pun) but there's no indicator lamp to say when it's on either.

[Gippslander]

This is going to sound weird but how do you know if you have an E=diff i have a D3 bought second hand recently just love to drive it but have no idea what it can and can't do as it is technically the wifes car. I still have the P38 just fitted a winch bar to it, so now it has 2" lift, Bilstiens and Khumo MT 33's so i am happy.

[psc]

The e-diff does make it easier for the T/C to operate (under slippery conditions) and if memory serves me correctly the rear side shafts on the e-diff equipped model are beefier.

Never driven a D3/D4 without the e-diff so cannot comment on what it adds dynamically.

[CSBrisie]

Check the FAQ's above - lots on this - inclduing a photo of the actuator sitting on top of the rear diff housing - which you can see in Off Road height if you squat down beside drivers side rear wheel and look in.
cheers

[camel_landy]

An e-Diff will improve off-road performance but as others have said, the Traction Control does help compensate for lack of one.

Just remember that an e-Diff is NOT a locking differential. Instead it uses clutch plates to offer a variable amount of resistance... All controlled through the Terrain Response system.

M

[unseenone]

Just remember that an e-Diff is NOT a locking differential. Instead it uses clutch plates to offer a variable amount of resistance... All controlled through the Terrain Response system.

M

As a non technical response, having seeing the inside of one of these diffs, I do not think that is entirely accurate. I believe that when the diff "locks" is is a locked differential. The "e-" in the diff is a clutch assembly, that spins a flywheel, which then engages with with teeth, that lock it. So, I think it is technically a locking diff when it is engaged, however, the computers tell it when to engage. I could certainly be wrong.

Pictured is some of the inner components, to include the actuator (e-) as well as the clutch plates, and a few other bits and pieces. A few more images are available, that would not attach for some reason.

[101RRS]

Retrofitting to a point so it operates the same as Landrover intended is possible but not realistic - surely an e-diff could be physically installed and rigged up to be manually controlled, not computer controlled. Afterall the diff responds to electrical signals from the relevant ECU. Wiring and a manual switch that has it either full on or full off should be possible.

Wish I had the money to buy a second hand unit and see if it would work.

Likewise I am sure a smart machinist like Ashcrofts could develop an airlocker that could be installed with the standard diff - a diff is a diff.

Garry

[unseenone]

There has been some luck with retro fitting to a factory e-diff, which is quite a project. It has been done, and documented if you are interested.

[Geedublya]

Retrofitting to a point so it operates the same as Landrover intended is possible but not realistic - surely an e-diff could be physically installed and rigged up to be manually controlled, not computer controlled. Afterall the diff responds to electrical signals from the relevant ECU. Wiring and a manual switch that has it either full on or full off should be possible.

Wish I had the money to buy a second hand unit and see if it would work.

Likewise I am sure a smart machinist like Ashcrofts could develop an airlocker that could be installed with the standard diff - a diff is a diff.

Garry

From what I have seen and read the actuating motor is a stepper motor not a DC motor. So you would require an appropriate stepper motor controller to drive the motor and know how many steps are required to lock the diff.

It would appear the the computer varies the amount of locking (clutch slip)and does not just go from 0 - 100% lock up on the clutch.

[d3viate]

I have one in the D3 and have seen the picture of the front and rear diffs pop up between the Tacho/Speedo when it cuts in while crawling in rocky conditions and a wheel lifts off into the air.
Vehicle certainly does progress easily in those precarious situations when it appears as it has stopped momentarily when rock climbing before it has cut in, but I have not driven a D3 without it so would not tell how easily a non fitted D3 would get up.
I think there is a clip on YouTube showing the difference between vehicles getting up a hill. The e-diff did get further but there was not much in it, whether it is worth the extra money would be an individual decision.
If you take the vehicle places that you do not mind dents from rock climbing, like Mitchell Plateau etc, then the extra ability may be worth it IMHO. If you don't get into those predicaments, I wouldn't bother.
I like it and would order another personally, if it saves me using the winch and staying in the drivers seat (air-con), it is worth it to me.

[camel_landy]

There is a very good writeup on DISCO3.CO.UK on converting a standard vehicle to run the e-Diff. :cool:

M

[dominicbeirne]

Here are the first lot of attachments for the job, one more to come

[dominicbeirne]

final attachment

Thanks to Spooky on disco3club.co.uk

Here is the link http://www.disco3club.co.uk/phpbb/viewtopic.php?f=9&t=943&start=20

[unseenone]

I just wanted to update my response as there was debate on the locking diff. I have confirmed that the e-diff is a true locking diff.

It is either engaged, or not engaged. when it is engaged, it is a true locker. The clutch plates in the differential are designed to minimize damage to the axle and prevent damage particularly during engaging and disengaging. It is theoretically possible for slip to happen, but not when fully engaged, by design, the clutch plates will never need replacement.

Presently there is an e-diff ready differential, which can be fitted to a non locking vehicle. You can later add the bit of kit to make it operational. The e-diff ready differential is heavier duty than then non-locking differential, and will be quieter, smoother and last much longer.

[camel_landy]

I just wanted to update my response as there was debate on the locking diff. I have confirmed that the e-diff is a true locking diff.

Maybe someone needs to tell the guys in LandRover... ;)

ISTR that the last time we spoke about this the answer came back that it isn't... but due to the nature of the beast, it behaves like it does.

I'll ask the question again & see if I can get the ear of one of the techie guys.

M

[jz-is-fishing]

[QUOTE=unseenone;1628990]
.....the clutch plates will never need replacement.

QUOTE]

I can't speak on this for sure but I just got a new rear diff, it would seem that the old e-diff will not allow the Actuator to engage and align itself. The reason would apprear to be that the clutches will not allow the actuator to engage. It is either that this is the reason or that something else is not moving or willing to move to allow the alignment. Techs best guess is that the clutch plates are frozen or that the flywheel is.:confused:

The diff had been overheated and the following day, after startup the traction reduced warning came on.

Just what i know.

[Graeme]

Presently there is an e-diff ready differential, which can be fitted to a non locking vehicle. You can later add the bit of kit to make it operational. The e-diff ready differential is heavier duty than then non-locking differential, and will be quieter, smoother and last much longer.
Is the e-diff ready differential a normal e-diff with some parts missing, implying that the e-diff is stronger than the standard open diff?

[gghaggis]

It is either engaged, or not engaged.

This description doesn't seem quite right? The purpose of the stepper motor is to facilitate a varying degree of lock, ie in certain TR programs some slip is allowed.

Cheers,

Gordon

[wrinklearthur]

This description doesn't seem quite right? The purpose of the stepper motor is to facilitate a varying degree of lock, ie in certain TR programs some slip is allowed. Cheers, Gordon

Hi All

To me it looks like the mechanism is a very clever arrangement, that has increasing amounts of controlled slippage until it fully locks.

But I am only going on the pictures and information on this thread.

Any one fitting a locker to a standard diff is running a risk of damage, to the half shafts and/or the differential, unless they beef the strength up, so it makes sense that Land Rover fit a stronger assembly with the E-diff.
.

[discotwinturbo]

Hi All

To me it looks like the mechanism is a very clever arrangement, that has increasing amounts of controlled slippage until it fully locks..

.

I have noticed that the diff lock lights up with 3 little arcs on the screen. Is this what you are referring to ?
Seems that when one is lit up then that maybe has a little slip, the second one maybe a little less slip, then the full on red display is fully locked. Book does not tell me anything about this.

[Graeme]

It makes sense to me to not slip as slipping could wear out the clutch plates quite quickly. The same effect as variable slippage could be achieved by varying the percentage of time the diff is locked. A stepper motor would allow very quick and thus short-duration locked and unlocked times.

[camel_landy]

Ok... Definitive answer time!

The e-Diff does NOT lock.

When wound up to max, you can still turn an e-Diff but you would require a force of approx 30,000nm!!

M

[isuzurover]

Ok... Definitive answer time!

The e-Diff does NOT lock.

When wound up to max, you can still turn an e-Diff but you would require a force of approx 30,000nm!!

M

Semantics. 30000 Nm (Capital N thankyou as it is named after Sir Isaac, plus there should be a space between the number and the unit) would unlock (AKA break) most selectable and auto lockers. (And where have you obtained this magic number?)

If you look at a cutaway of the e-diff, it clearly contains carbon fibre clutch packs, similar to rally cars with hydraulic diffs. It can seemingly vary from open to (effectively) fully locked.

[camel_landy]

(And where have you obtained this magic number?)

Have you forgotten where I work??? ;)

M

[Graeme]

The clutch for a manual gearbox doesn't lock either, nor do the hydraulic clutches in automatic gearboxes but by design they all effectively do.

[unseenone]

Is the e-diff ready differential a normal e-diff with some parts missing, implying that the e-diff is stronger than the standard open diff?

The e-diff ready, is less the stepper motor. The locker and non locker are slightly different, different bearings are used, so internally they are not totally identical. As far as a particular strength of one or the other, I am not rendering an opinion.

The idea being providing a e-diff kit, with the extra bits such as wiring, ecu, stepper motor, so you can convert to a locker after that. I agree as to the responses on the description of the clutch plates. You have to have give in the system or things would / could break, and still do on occasion.

[Tote]

I have an interesting scenario to ponder regarding my E diff. The other day I noticed a small occasional clunk when turning corners and didnt think much more of it. On the weekend I went for a drive to Werris Creek and near Dunedoo i got a reduced traction warning after coming through some water on corrugated dirt which I couldnt clear. When I got to Werris creek and turned around the clunking noise had got lots more serious and I figured that either the centre diff or the rear one was locked.
I drove home in the wet and figured out in the carpark at Phesents nest that part of my problem was the wires hanging down from underneath the back axle.

This afternoon I did some surgery and re spliced the wires back together. The cause of them getting broken was the flat plastic tags that hold the wires off the diff housing had broken and I suspect that they got entangled in the CV or axle. After I repaired the wires the reduced traction warning was still on and on investigation there was a stress fracture in the red wire where it goes into the plug that attaches to the diff. Repaired this and the reduced traction warning dissappeared.

When I backed the car out of the shed the diff still appeared to be locked but after a couple of circuits in the high school car park it seems to be behaving itself. Tomorrow will tell further I guess. I have the truck booked in for a service next week so I'll get them to test the actuator if they can.

So My questions are:
Is the plug that attaches to the bottom passenger side of the diff housing the temperature sensor?
If the temperature sensor went open circuit would the vehicle try and lock the diff as a failsafe?
Or is my wiring issue coincedental with a faulty actuator or other problem with the diff?

Regards,
Tote.

[Graeme]

The temperature sensor is on the lower left side of the diff and it has a red wire and a yellow wire attached. I couldn't see any reference in the WSM to the diff locking when any type of fault occurred and I suspect the exact opposite would occur.

[Tote]

Diff behaviour hasn't changed this morning so the temperature sensor wiring problem must have been coincedental.
Looks like I have a failed actuator or a failing diff.........

Regards,
Ian

[Tote]

Changed the diff oil today and the diff was binding as it was backed off the hoist. A lap around the carpark with the new oil and it has been behaving itself. No actuator faults or error messages present since I did the rewiring so I think that that may have been unrelated. My strategy is going to be to change the oil again in a couple of thousand KM and see what happens.

Regards,
Tote

[isuzurover]

As a non technical response, having seeing the inside of one of these diffs, I do not think that is entirely accurate. I believe that when the diff "locks" is is a locked differential. The "e-" in the diff is a clutch assembly, that spins a flywheel, which then engages with with teeth, that lock it. So, I think it is technically a locking diff when it is engaged, however, the computers tell it when to engage. I could certainly be wrong.

Pictured is some of the inner components, to include the actuator (e-) as well as the clutch plates, and a few other bits and pieces. A few more images are available, that would not attach for some reason.

Thanks - great pics. However do you have pictures of the inside of the half of the diff hemisphere with the engagement wheel? I assume there is some sorrt of cam which increases the force as the wheel is rotated by the stepper motor? Ideally also measurements of the change in cam height through the full travel of the wheel?

The e-diff looks like it would suffer the same clutch plate wear issues as an LSD, and eventually become less effective or totally ineffective (as happens with most LSDs). It doesn't look like it would be hard to convert to a proper locker (with either electric or pneumatic operation) though...

If someone wants to lend me an e-diff - even a broken one, I can get some final year mech eng students to do it as a project.

[gghaggis]

If someone wants to lend me an e-diff - even a broken one, I can get some final year mech eng students to do it as a project.

I don't think it would be hard to come up with a circuit that would lock up the diff completely, but then again a) it's not necessary, as the diff works brilliantly as it is and b) the components would probably have to be strengthened to cope with long-term 100% lock-up. One of the greatest advantages of this type of locker is the durability of the standard components in the rear drive-train when compared to the normal wear/breakage levels that many pure lockers either suffer or are a causal agent to.

What _would_ be incredibly useful, would be to override the centre eDiff controller, such that in emergency situations where one has broken a CV joint or halfshaft, it can be locked and the car is more easily drivable. I asked LR UK about this, but their comment was that it's not possible. I'm sure that statement could be proved wrong :twisted:

Cheers,

Gordon

[isuzurover]

I don't think it would be hard to come up with a circuit that would lock up the diff completely, but then again a) it's not necessary, as the diff works brilliantly as it is and b) the components would probably have to be strengthened to cope with long-term 100% lock-up. One of the greatest advantages of this type of locker is the durability of the standard components in the rear drive-train when compared to the normal wear/breakage levels that many pure lockers either suffer or are a causal agent to.

What _would_ be incredibly useful, would be to override the centre eDiff controller, such that in emergency situations where one has broken a CV joint or halfshaft, it can be locked and the car is more easily drivable. I asked LR UK about this, but their comment was that it's not possible. I'm sure that statement could be proved wrong :twisted:

Cheers,

Gordon

I'm sure I could get a mechatronic student to do the latter as a project.

However I disagree with some of the first part of your post. While I am sure the e-diff works brilliantly now, for those who wish to keep their D3/4/RRS long term, the clutch packs will need to be replaced or reshimmed on a regular basis as they are a moving/wearing part - or the whole diff replaced at $3000(?) a pop.

MDE/ARB/Ashcroft etc lockers also have internals that are no stronger than LR HD diffs. The last generation MD locker used off the shelf LR side and spider gears, and the MD salisbury locker simply has splines added to the side of the hemisphere - no upgrading is needed. I believe ARB and ashcroft spider and non-locking-side side gears are the same as OEM too.

The e-diff already has upgraded axles, and is clearly a fairly sizeable 4-pin diff. I doubt conversion to a "proper" locker would increase the failure rate.

[gghaggis]

I'm sure I could get a mechatronic student to do the latter as a project.

Good idea! (edited to add: it must be possible, because I recall the LR cutaway project in 2005 demonstrating an eDiff on a bench, with a 3-position switch to control it)



However I disagree with some of the first part of your post. While I am sure the e-diff works brilliantly now, for those who wish to keep their D3/4/RRS long term, the clutch packs will need to be replaced or reshimmed on a regular basis as they are a moving/wearing part - or the whole diff replaced at $3000(?) a pop.

But the wear rate in terms of km's driven is probably only a fraction of that in the LSD or auto-locker setups, as it is only invoked rarely, and for very short periods of time. I've not heard of anyone needing to overhaul a D3 diff due to normal wear and tear. So contrary to your implication ("the clutch packs will need to be replaced or reshimmed on a regular basis") I don't believe there would be much call for such a service.



MDE/ARB/Ashcroft etc lockers also have internals that are no stronger than LR HD diffs. The last generation MD locker used off the shelf LR side and spider gears, and the MD salisbury locker simply has splines added to the side of the hemisphere - no upgrading is needed. I believe ARB and ashcroft spider and non-locking-side side gears are the same as OEM too.


Don't think that's true in the case of the Discos - my series 1 had different gears.

Cheers,

Gordon

[Graeme]

the clutch packs will need to be replaced or reshimmed on a regular basis as they are a moving/wearing part - or the whole diff replaced at $3000(?) a pop.
I suspect that several recalibrations could be needed over the life of the clutch pack as the ecu doesn't auto-adjust, but that's just a simple diagnostic function.

Is there a diagnostic function (T4, Faultmate etc) to lock the centre diff? I'll have a look at options with Faultmate next time.

[Graeme]

Changed the diff oil today and the diff was binding as it was backed off the hoist. A lap around the carpark with the new oil and it has been behaving itself. No actuator faults or error messages present since I did the rewiring so I think that that may have been unrelated. My strategy is going to be to change the oil again in a couple of thousand KM and see what happens.

Regards,
Tote
Sounds hopeful. How many kms since the oil was changed?

[Graeme]

Good idea! (edited to add: it must be possible, because I recall the LR cutaway project in 2005 demonstrating an eDiff on a bench, with a 3-position switch to control it)Its only a 12V stepper motor so just needs the ability to cut power when there's excessive current draw to prevent the motor from burning out.

[gghaggis]

Its only a 12V stepper motor so just needs the ability to cut power when there's excessive current draw to prevent the motor from burning out.

That's the only real complication I could come up with, so this could be a plan. Simple switch on the transmission tunnel that activates and controls the stepper motor to lock the central diff. That way the car is drivable in cases of driveline failure. I suppose it could be fitted to the rear as well, but not sure of the advantages of that.

The only question would be what the rest of the systems would do - the feedback circuit is a little complex ...........

Cheers,

Gordon (more wine required)

[rmp]

I think the summary is that e-diff is in effect a locking diff, even if it's not technically a locking diff. If you call it a limited-slip, which it really is, then that creates entirely the wrong impression of its capabilities.

With a true locking diff if you wanted to turn the axles at different speeds you'd need to literally break the diff to do so. Clearly with the e-diff you'd just rotate clutch plates...but 30k Nm it may as well be locked solid for all practical purposes!

[Tote]

Sounds hopeful. How many kms since the oil was changed?

About 50,000

Regards,
Tote

[camel_landy]

I think the summary is that e-diff is in effect a locking diff, even if it's not technically a locking diff. If you call it a limited-slip, which it really is, then that creates entirely the wrong impression of its capabilities.

Exactly, which is why we try to avoid using some of the more 'traditional' terms when describing its operation. It isn't a locking diff, it isn't really a limited slip diff... It is an e-Diff.

M

[Graeme]

About 50,000

Regards,
Tote
I wondered if it had been longer. Mine were changed at 40K and will be changed again at the 100K end of warranty service.

[isuzurover]

... I've not heard of anyone needing to overhaul a D3 diff due to normal wear and tear. So contrary to your implication ("the clutch packs will need to be replaced or reshimmed on a regular basis") I don't believe there would be much call for such a service.

Serious question - how would you know if the clutch packs were worn? By all accounts the ETC works well on its own, and the electronics simply control stepper motor function/position (lighting up the e-diff light as appropriate), without anything to measure that the e-diff is working?

i.e. - If the stepper motor engages the e-diff fully but the wheels are (still) turning at different rates as measured by the wheel speed sensors, will you get an error message at all?

[Tote]

I'd be surprised if it didnt. When my temperature sensor on the diff went open circuit due to an air gap in the cabling :wasntme: The display logged a "warning traction reduced" error. I reckon that if the computer can figure that it's locking the diff and that the wheels are turning at different speeds it would probably log a reduced traction error (maybe)

Regards,
Tote

[~Rich~]

Jeeze okay this is the right thread:
Anyone want an EDiff?
Sydney - $1300

Land Rover Locking Rear Diff | Other Parts & Accessories | Gumtree Australia The Hills District - Annangrove (http://www.gumtree.com.au/s-ad/annangrove/other-parts-accessories/land-rover-locking-rear-diff/358404012)

[Graeme]

I know that address - DPL.

[~Rich~]

;)
I did too Graeme.

[Cairns Rob]

I have been following this thread with interest as there are some weird noises coming from the back of my car. I have just taken it to my local dealer here in Cairns and they have told me that the E-Diff actuator motor is seized and needs replacing, they have quoted me $2600 for the privilege. Seems excessive to say the least any info, or advice would be much appreciated.
Regards Rob

[isuzurover]

I have been following this thread with interest as there are some weird noises coming from the back of my car. I have just taken it to my local dealer here in Cairns and they have told me that the E-Diff actuator motor is seized and needs replacing, they have quoted me $2600 for the privilege. Seems excessive to say the least any info, or advice would be much appreciated.
Regards Rob

You could probably track down the manufacturer of the stepper motor, and see if they are available direct.

You may also be able to repair it, if t is gummed up or rusted. 4-bolts and electrical connector to remove...

[Graeme]

4-bolts and electrical connector to remove...It might need recalibrating after refitting.

[Tote]

I have been following this thread with interest as there are some weird noises coming from the back of my car. I have just taken it to my local dealer here in Cairns and they have told me that the E-Diff actuator motor is seized and needs replacing, they have quoted me $2600 for the privilege. Seems excessive to say the least any info, or advice would be much appreciated.
Regards Rob

I have had the rear locker jam up on mine. noticible when driving around town with a locked diff. I changed the oil which was black and dirty, reversed the car and it gave one final bang as the diff released and hasn't given any trouble since. I changed the oil as a precaution 12000KM later and it was clean. This happened at around the 200,000 Km mark. Not sure if the dealer had changed the oil at 130K as they are supposed to but I couldnt find any reference to them charging for it:no2:
Anyway. If the diff appears to be locking an oil change is cheaper than a new actuator.

Regards,
Tote