Four Wheel drive

[jon_t]

Have many 4x4 cars got difflocks.?

[Fredxx]

I would say most do, or should I say few don't. There are various types of diff-lock from a hard dog engagement, to Quaife style to viscous coupled. Some make MOTs problematic.

Some might use traction control to mirror the diff-lock experience, as indeed do most modern cars on their driven wheels, but that's not the same.

[gareth evans]

The Landrover Defender that I had 24 years ago had one, but I wasn't used to it, and when going up a lane onto Salisbury Plain with the local Landrover club, I couldn't get past this slippery rock until someone walked back and nudged me about the difflock.

Doh! :-(

That became known to our local group as Difflock Hill!

We had a few other such names, Dead Mazda Junction, Junior Hacksaw Lane, Watch Out There's A Wasp lane, to name but a few :-)

[John Rumm]

If by "cars" you mean cars rather than SUV/Off road vehicles, then manual diff locks are less common IME. Many will have limited slip diffs though - especially the more performance oriented cars.

[www.GymRats.uk]

OK, so this is an area of great confusion. In "olden" times where proper 4-wheel drive (Defender, Discovery etc) were mechanically connected by drive shafts there were 3 diferentials.

1 on each axle and one in the centre.

The standard factory fitted diff-lock would only lock up the centre diff. ensuring drive went to front and back axles but this was still useless if one wheel on each axle had no traction for example a cross-axle situation going diagonally across an obstacle.

Enter the advanced off-roader soloution of an after-market rear diff "locker" (a pretty specialist addition for the proper expeditionist); or the ultimate, a front AND rear diff-lock addition.

Jump forward a few decades and an automated form of "fiddle brakes" came along with the invention of stabillity control (ESP etc) which could automatically apply brake pressure to any of the 4 wheels individually if spin (or incorrect steering wheel to yaw rate etc) was detected by ABS and other directional sensors. In fact, the first Discoveries to feature it still retained the centre diff and diff-lock internals but the handle/lever to engage the D/L was removed! Often re-comissioned by owners because a broken 1/2 shaft would disable the vehicle relying on elctickery whereas a mechanical centre diff-lock would still push power to the remaining intact axle.

And now... all the hydraulic "automatic" 4x4 systems (4-Motion etc) use pumped oil to effectively lock-up the central clutch pack that replaces the old mechanical diff thereby giving a superior (under most circumstances) replacement to the mechanical central diff-lock by offering variable torque distribution between front and rear "axles".

So, for example, on my VW T5 Transporter I ALSO had the optional diff-lock which operates by locking the rear diff. Rarely if ever required just like the original discoveries manufactured without a rear D/L but on the rare occasion 1 or both front wheels and one wheel rear suffer zero traction the D/L will ensure one wheel still gets drive (remember the X-axle scenario)

Somewhat simpified answer to your question would be, very few simply because they already have a completely aoutomated replacement to the centre diff which will, when required, automatically lock front and rear drives.

And speaking from experience, I DID get my discovery stuck going over a large flat rock laying diagonally across a muddy up-hill track, the D/L was completely useless. Whereas my Transporter has NEVER got stuck no matter how hard I try!

Oh, I should also add, that when I was an aprentice (50 odd years ago), my Boss of the agricultual engineering company bought himself the original Audi Quatro (the legendary rally killer). It had selectable diff-locks for all 3 diffs. It was an absolute beast.

HTH

Right, Back to work for me. :)

[jon_t]

Thanks for that info very informative.....my short wheelbase G-Wagon had 3 independently selectable difflocks, but the Golf R didn't appear to have any.

[The Natural Philosopher]

There are so many variations. E.g. wheel locks on the front axle to go into 4WD , centre diffs that lock up under shear. Various limited slip differentials front and rear.

It really is a question of what the vehicle is used for - towing the pony box off a muddy field or climbing a 45° rock face...

[Andrew]

Ha. The suzuki SJ410 only had a dog clutch in place of a centre diff. If you forgot to unlock it after returning to a hard road, making the car 2WD only, then the very next corner was 'interesting'.

[www.GymRats.uk]

On 10/05/2023 18:30, jon_t wrote: <snip>

As has been mentioned, the sporty cars may well have a limited slip diff on front and/or rear whereas the central diff is as described otherwise when tanking it around sharpies and one or both inside wheels lift off you'd lose drive.

Again, in my late teens an older mate had the original Series 1 Escort RS Turbo bought new (B636 XHU) "only" front wheel drive but factory fitted with a proper limited slip diff. I believe it was one of those things where the manufacturers had to make 500 production cars to be rallied in the production class or something.

I drove it a lot as it meant he could drink. His instructions were always "give it more gas" when a bend tightened as the outer wheel would load up and the LSD would then pull it around the bend. Only 130 BHP so nothing compared to today but one of the most fun cars I've ever driven.

[www.GymRats.uk]

:)

I thought corners were always "interesting" in a Suzuki Jeep?

Nearly bought one but was put off by the stabillity concerns and me not being one for sedentary driving on 2 or 4 wheels, it would have ended in tears.

[The Natural Philosopher]

The early Freelander was 'interesting' as the viscous lock centre coupling would lock up if it detected faster wheel spin on the front axle. ...Including if you put new tyres on the back, but not on the front...

[jon_t]

Both My 1963 Jaguar 3.8 Mk2 (633 HRY) and my (1971) Ford RS1600 (NEC 857K) had limited slip diffs.

[gareth evans]

I had a Samurai and the owners handbook stressed that care was needed when turning sharp corners!!!!!!

[Vir Campestris]

I'm no expert, but I though the original Land Rover was like that too. No centre diff.

Andy

[Adrian]

Up to and including the Series III, yes. The Series III went out of production ~1983/4. I think that after that they were permanent 4WD, but I never drove one.

Adrian

[SteveW]

I think that you might be right. Didn't they normally leave the front drive disengaged for on road driving and not need a centre diff when off-road?

[Roger Mills]

My recollection is that they had a transfer box with front and rear prop-shafts which ran at the same speed (no diff between them) but the front half shafts didn't actually drive the front wheels unless you (manually) engaged the hub locks.

[SteveW]

Weren't those optional freewheeling hubs, meant to save the wheels dragging the swivels, half-shafts, diff, prop and gearing around? 4WD was engaged using the yellow lever or 4WD/low box, with the red lever.

[Adrian]

Free wheeling hubs on the front were an option. Yes, they were meant to stop the wheels driving the front transmission when the transfer box was in 2 wheel drive mode (less drag, less noise).

Adrian

[Bob Eager]

Hub locks were an optional extra. They may even have been aftermarket/ third party. My 1952 Series I didn't have them.

The transfer box was as you describe, with low, high and neutral settings. That was the red lever. 4WD was engaged by pressing the yellow spring loaded knob, and disengaged (after stopping) by moving the transfer lever to another position (and back again if required).