Andy W

As above....... is the Series II disco permanent 4WD or is it for normal conditions 2wd with selectable 4wd?
You could help to settle a 'discussion'

Andy W

drumsterphil

iTrader: (1)

Permanent 4wd.

Think you'll find that Land Rover do not make any products with anything other than permanent 4wd.

DP.

Andy W

Cheers.
A

Reffro

The Freelander is only part-time four wheel drive but they have never admitted as such in their advertising, still claiming it to be permanent.

dazc2

The Land Rover Disco is not permenant 4x4......it is switchable rear wheel drive and 4 wheel drive hi and low ranges.........it hasnt got the viscous couplings of the Range Rover and cant tolerate being on tarmac unless its in 2wd setting, if you run a Disco in 4x4 on the tarmac you will suffer torque wind back and will snap half shafts in the axles or rip the splines out of the diff..........this was true for anything older than the new shape which may still be the same transfer box as i know very little about the recent face lifted versions.

turbonutter

Only used to driving Landie 110s for 5 years so I may not be able to answer but - the 110 is permanent 4 wheel drive with a seperate stick to select low range gears i.e. the gears you use when trying to get out of mud, snow, ice etc. it's always 4wheel drive but virtually has '2 sets of gears'.

I believe the Disco's are pretty much similar. Range Rovers, Land Rover Freelanders, Discos and the 90 and 110s share a lot in common for chugging off road, even if the shells are built completely differently.

polarbearit

Right well I'm very confused!

Whatever year discovery one was launched at a motorshow I was there (though not even old enough to drive at the time ) and then it was definitely full time 4*4 and I'm sure in 1996 (I think) the discovery was still full time 4*4 when I went round the Landrover offroad course... So when did it change? Or did I totally misunderstand the literature and Landrover people I met?

Cheers,

Confused Jon

pacenote

Well the Disco I had (93MY) was permanent 4WD with a high and low range box. Only ever used low range when off road, not recomended on tarmac. I think current model is same transmission system.

zax

Was having a similar argument with Mrs Zax who wants to replace her Ford Explorer with something similar. What I could use is a website that explains in terms even an idiot like me could understand how each "type" of 4wd system works (subaru, VAG quattro/4-motion etc. etc.) and what the benefits/drawbacks of each are. Is there such a site?

MikesWagon

Reffro,

power on the Freelander is split, (65/35 at an estimate from a local Land Rover guru) between front and rear, in normal driving conditions. The earlier post describes the mechanics with the viscous couplings etc, but that still makes it permanent 4wd. It doesn't have to be 50/50, and it's certainly never 100% to the front wheels (unless both the back wheels are off the ground possibly? - haven't tried yet...)

I don't know how the CRV etc work, so won't comment on them

Mike.

dazc2

I shall repeat my origional statement................

Disco's, 90's and 110's all share the same transmition and are NOT.......i repeat NOT permenant 4x4...........

If you run any of these vehicles with the diff lock engaged on tarmac you WILL without fail destroy either the transfer box, front or rear diff, front or rear propshaft or any of the half shafts (driveshafts).......as its designed for use off road when grip is compromised the problem of torque wind up in the shafts is not a problem as any torsion in the shafts is spun away in the loss of grip.........on the road however this is not possible and put the drive shafts and other coponents under great strain and also give the vehicle some odd driving characteristics which will seem like a binding brake

The diff lock locks the central differential within the transfer box to divert drive to the front diff........without the diff lock engaged the front wheels and propshaft only free wheel.

P.s............i have 7 years experiance on these vehicles ranging from MY73 90's and 110's to MY00 Discos, 90's and 110's plus MOD spec Landrovers and landrover ambulances and also forward control Landrover 101's........Range rovers are different again with a different transfer box and a viscous coupling instead of a mechanical diff lock

Andy W

I'm not being a smart A$$ or trying to take the mick, I am happy to take your word for it but your post refers to locking the diff, not to the perm or not nature of the 4x4 system, If you lock the diff on a STI V ltd Type R you will get transmission wind up and cause damage too, the car is still AWD.
Looking forward to lots of technical discussion.

Andy

^Qwerty^

Ain't there a "2nd" gear lever that allows you (as mentioned above on Jap cars) to go from:

1) Rear Wheel Drive
2) Four Wheel Drive
3) Low Four Wheel Drive

Im trying to remember how my Range Rover worked... but its a long long time ago.

Diablo

At the risk of being confrontational, I'm not sure if I agree with that.

Any free, non torque biasing differential will distribute the torque of the input shaft 50:50 accross the output shafts assuming zero or equal load on both output shafts. This is the reason that rear wheel drive cars with no form of lsd or traction control don't just have 1 wheel drive.

Of course, if one of the output shafts is under more load than the other, a higher proportion (up to and including 100%)of the torque will go to the output shaft with less load.

In this (4wd) application, the output shafts from the centre diff are the propshafts going to the front and rear axles.

An open centre differential simply exists to allow each axle in 4wd to rotate at different speeds . A diff lock simply locks the centre diff so as to remove the possibility of one or other axle receiving 100% of the torque, thus effectively rendering the vehicle 2wd and getting it stuck.

Agreed with you on why you shouldn't use a diff lock on tarmac.

To be specific, and answer some points raised earlier,

In the first prototype (1948?) and used in early production, in order to avoid rigid gearing between the front and rear axles the engineers fitted a free-wheel device between the transfer box and the front prop shaft, thereby allowing the front wheels to overrun the rear ones if required

From 1950ish the transmission became optional four-wheel drive or rear-wheel drive, selection being by means of a lever.

In 1979 the Series III saw the introduction of the V8 with the Range Rover's full time 4wd LT95 transmission.

With the exception of the introduction of the V8 with the Range Rover's full time 4wd LT95 transmission in 1979, permanent four-wheel drive was introduced with the 90 and 110 in 1983 (although and selectable four-wheel drive was optional on One Ten four-cylinder models until 1984)

Range Rovers originally used a Salisbury limited slip differential between front and rear axles. Not sure what it is now.

All Defenders have full time 4WD with open/free but lockable centre diff, as in my example above.

The Discovery was orginally designed on a range rover chassis, but with a free but lockable centre diff and not the LSD of the rangerover. It has full time 4WD.

Series II Discoveries have 3 open diffs, and the traction is controlled by braking the spinning wheel or wheels to apportion torque to the wheel or wheels with most grip. It does have a mechanical centre diff lock but this can only be operated from under the car and disengages the traction control.

So getting back to the quote, I think its bollox

But then it might be down to definition. However, Defenders and Discoveries which (agreed) share the same transmission type do not "free wheel" at the front without the diff lock engaged. They have an open centre diff.

Place a series one Discovery on sheet ice, leave the centre diff open and i guarentee you it will spin all 4 wheels if you drop the clutch.

But I'm open to be proved wrong

D

Diablo

So, to answer the opening question, Series II Discoveries have permanent full time four wheel drive, but with three open diffs, front, centre and rear, and traction control in place of internally operable diff locks.

D

Phil_

"Disco's, 90's and 110's all share the same transmition and are NOT.......i repeat NOT permenant 4x4..........."

Absolute twaddle.

^Qwerty^

But will it go around a corner?

Tommy 2000

What a confusing debate!!

dazc2, on what are you basing the statement:

'Disco's, 90's and 110's all share the same transmition and are NOT.......i repeat NOT permenant 4x4'?

I am sure my Defender 90 was permanent 4x4 and it was always spinning all four wheels when doing serious off-road work. There was certainly no option to select 2 wheel drive, only a high/low shifter...

Disco Boy

Having, at vast expense, had a '96 Disco for four years (sold it in September for a MY01 WRX wagon with PPP), I can confirm that it had permanent 4WD, and a lever that would transfer between the high & low ratio boxes and lock the diffs.

Having driven off-road with the diffs locked, it was sometimes necessary to reverse a little to 'unwind' the diffs. It was also like driving on ice.

Diablo

One man's bollox is another man's twaddle..



d

logiclee

Early Land Rovers upto the series 3 were not permanent 4 wheel drive they had a dog gear which you had to engage to get the front wheels into mesh.

The later 90,110,130 Land Rovers and all Discoveries replaced the doggear arangement with a centre differential (Simimilar to the Range Rover of that time) making them permanent four wheel drive. Drive is permanently distributed to all four wheels. With all 3 diffs being open it is possible to get stuck if one of any of the wheels looses total traction (ie, its off the ground). To give these vehicles off road capability Land Rover fitted them with an electronicaly operated locking centre diff. This can be selected in high range and automaticaly engages in low range.

I drive a 110 every day and its possible in the wet when pulling out of junctions to get both the front and rear inside wheels spinning without difflock.

If we were to say the centre diff had to be locked all the time to be permanent four wheel drive then NO road car is permanent 4x4.

Permanent four wheel drive means that the drive is permanantly sent to all four wheels so the scoob and Disco's a have permanent four wheel drive. The fitting of viscous or electronic locking diffs are just there to further control traction.

Lee

dteagles

.....flame suit on.......

does any of this matter?

As long as it doesn't get stuck in the mud/snow & shi$ .......


Darren.

Andy W

I only asked as I was interested!?!? But interesting debate!

dazc2

Ok,

Then why on a 1995 Landrover 110 was i able to raise the rear wheels, whilst leaving the front wheels on the floor and run the vehicle in 3rd gear for over 4 hours to diagnose/test a differential pinion seal leak?

i cannot speak for the newer vehicles............

dazc2

I know some had a different front axle as well with free wheeling hubs which had a **** in the centre which you turned to engage........

the centre diff in the transfer box was not transmitting drive to the front wheels and didnt do until i engaged diff lock is why i could do that.......

i will expect that some of the newer vehicles are permenant 4x4 but not a lot of the old vehicles are

Andy W

Just as an example on a 2wd vehicle with an open diff-if one of the driven wheels is off the ground then all the drive goes to that wheel, the other does not turn,does this mean it is one wheel drive?

dazc2

no.....if on a 2wd vehicle not equipped with an LSD of any form it will direct the power to the easiest wheel to turn....a limited slip diff limits the "slip" between the 2 wheels.......a viscous coupling heats up when 1 wheel starts spinning and then locks so the drive then diverts to the other wheel preventing loss of drive....

dazc2

i shall not say any more on the matter

Andy W

Daz, I am not having a go, and my knowledge of mechanics is very rudimentary and I appreciate your input.

A

dazc2

Im not upset or anything....i just know that it is pointless me carrying on an arguement that i have insufficient background knowledge on........i have worked on countless amounts of these things but i cannot really speak for newer equipment as most of my experience is related to the older Landrovers........i do know the new Discoverys are permenant 4x4

on ours at work it hasnt got the front propshaft as it has collapsed...but it still drives even without the diff lock engaged..........with a free wheeling (none LSD) diff this would not happen as it would spin all the power away through the front prop flange as its the easiest for the engine to turn.