Locking Differential Differences

[RoaryV8]

Just thinking lately about getting lockers on the range rover as it seems to have issues with TC and ABS.

Are there much performance difference's between ARB, KAM, Detroit?

I gather ARB are better as twice the price, but also need all the air set-up too, But the others are they simply bolt in and go?

[Range Rover Blues]

Quick rundown as I understand it.

True track AKA auto torque biasing are a free running diff that uses clever gears to provide more torque (between 3 and 5 times) to the wheel that isn't thrashing about in space, if you have any grip on the spinning wheel then these work well. Because they do no lock they are suitable for the front axle and also work well with brake-intervention traction control.

Tor-Sen as used on very early Audi Quatro is a similar diff that uses worm gears in place of the planet gears of a noraml diff, the super high gearing of the worn/pinion means they lock up unless under almost no load. Hugely dependable but horrendous backlash.

Limited slip diffs have friction plates inside that need setting up. They use cams in the diff cage to increase the pressure on the clutch packs under power so they lock up more under drive, again if you have no grip you get the minimum lock. they are always partically locked though and effect handling when fitted to the rear (understeer) they are not nice to use in the front though some hot hatches have them, they have to be adjusted to give very little lock unless under high power.

both ATBs and lockers are common in tuned road cars, along with;

Viscous diffs, as used in the range Rover have a normal diff with a viscous hub connected, it contains a fluid that thickens when heated/agitated so the diff runs free if it's turning slowly but as the speed of slip increaes the fluid thickens and the viscous unit locks up. it contains multi plates that run close together so the fluid sticks them together. If they overheat the fluid burns and dries up, ruining the unit. Fully automatic, they are great on the road but never truely lock up so not as good off road, particulalry in the centre diff. Also found in Ford 4wd systems' centre and rear diffs. Cavalier and Freelender use a visocus hub in place of a centre differential, they use it as a freewheel such that if the front axle speed drastically exceeds the back axle the fluid locks up and transmits drive to the back. Willis overland Jeeps and early series one LR used a sprag clutch to the same effect when going forwards, but driving the rear wheels primarily. Makes them a hoot to drive I'm told.

Detroit lockersd are only suitable for the rear because they are actually not a diff, they are a locking free wheel unit. The diff is locked all the time and only transmist drive to the slowest wheel. in a corner, provided there is enough grip to drive the mechanism, the faster wheel unlocks cams within the diff to allow it to turn faster but without drive. There is a noise assosciated with their operation. They are automatic in operation and very popular due to their strength and cost but as they only drive the inside wheel on a corner they increase the speed difference between front and rear axles which will cause more strain on a viscous centre diff..

ARB air lockers use air pressure to throw a locking dog into an otherwise conventional or "open" diff, albeit a strong 4 pin unit. Great for either axle they have good road manners and 100% lock when needed. Sometimes you don't want a locked up axle, the driver gets to choose.

KAM are as I understand an electicly operated locking diff, no expensive air pump, so no tyre inflator either, but expensive axle mods instead to fit the cover plate with operating mechanism. KAM diffs can be used with their halfshafts which are very nice bits of kit.

There may be others but for a LR I think that covers the common ones, viscous hubs crop up in the B-W transfer box found in post 1987 RRC.

I have ARB, love 'em, would buy again, I have total control of them and they are tough units. If you want bolt in and go then truetrac in the front, I believe they are specific to one end or the other, and truetrac or detroit in the back. Had a Detroit though, never again.

[Range Rover Blues]

P.S. the RRC only had traction control on the back and after a limited time it will cease to function in order to protect the brakes from overheating.

[Steve 90]

Have a look at the new offering from Ashcroft.

Works in a similar way to an ARB but they have built it in a way that does away with the problem areas. Air leaks are a thing of the past and it engages and disengages quicker (IMHO). An excellent unit thats competitively priced. We've been using one for a while and its brilliant.

Cheers.

Steve.

BTW, We are what would be called a heavy user, We took 1st place at Manby/90 degree challenge first time out with it. Ive 100% confidence in the unit.

[RoaryV8]

Had a few replies about ARB is the best, so looks like im going to be saving for a bit and getting a front and rear set-up.

Can i use the RRC standard Air set up to run the lockers?

Now converted to coils so its sat there not being used.

[Bowie69]

You could, probably, but TBH wouldn't you rather have the increased ground clearance from removing it? They sell for good money on ebay, more than enough to pay for a proper ARB compressor, or a T-Max DIY version.

[RoaryV8]

they dont seem to big under the truck, But if they sell for decent money then i might get that off this afternoon then

[Hybrid_From_Hell]

Have a look at the new offering from Ashcroft.

Works in a similar way to an ARB but they have built it in a way that does away with the problem areas. Air leaks are a thing of the past and it engages and disengages quicker (IMHO). An excellent unit thats competitively priced. We've been using one for a while and its brilliant.

Cheers.

Steve.

BTW, We are what would be called a heavy user, We took 1st place at Manby/90 degree challenge first time out with it. Ive 100% confidence in the unit.

^^

Steve

Is it these ? :

http://www.ashcrofttransmissions.co.uk/index.php?act=viewProd&productId=253

But its not a Locker and I thought you had full lockers ?

Nige

[Retroanaconda]

To me the Kam electric soleniod style appeals, but I am put off by the need to mod the axle housing. As a result, an ARB is probably the way I would go, since I have an air system halfway in place already.

[RoaryV8]

Certainly does make sense if the air is already there

[Mark]

Air also means you can run freespools on your winches too, should you decided to go down that route...

[ricky tango]

i have the kam full setup front to back and all i can really say to your above kam downfalls are ( what expensive axle mods?)

the system comes well documented, and with its axle mod improves on the weakest part of a lr axle casing the diff pan ( many of which are already weaping around the bottom any way

before fitting my lockers i had qt diff guards and in all honesty i hated them as they trapped mud and stones to a point that they would speed up how quickly a diff pan would normally take to rot out

kam are a company and like all companies if you ask them for a basic prep on an axle you will get a better price than they might advertise for say a full axle strip /mod and rebuild. For most the hardest bit is the welding (most of us have access to a grinder and a paint brush so dont be a stranger and give them a call for a personal quote and not an internet glance from other members on here doing a rough tally up without taking into account on potential discounts you will receive by buying a full kit with a one off postage rather than individual prices

phone them all up throughout the week on your breaks and you'll get a better picture of who they are ( there prices or name brands they stock arent always the things you should base these things on )

kam are a similar distance for me as i am from ashcroft. I have friends running ashcroft and arb combos with nothing but good words (and the same for the service they reecieved) i am actually off to see dave at ashcroft tuesday for a rebuilt transfer box as i'd like to fit once and forget for a while and from my dealings so far he is a very nice bloke and has offered a good deal with regards to a trade.

i liked the service i got from kam

the other thing that swung it for me was all there items at kam are there's built in there unit and guaranteed by them if i have a warrantee claim i will return to them and they will respond immediately. I'm not sure on arb's warrantee through ashcroft. I know they will be loyal and not mess you around but if it comes down to an arb component failure they are as such a middle man and may have to send the unit off before you see a replacement this would be down to arbs testing and returns policy tho and not the re seller/ dealers

i believe the above to be correct in terms of there business although yet again i am a man at a laptop with a general understanding of business (going from my previous experiences with other companys and parts)

we have on the forum both members of kam and ashcrofts and neither will rule out the other, its just not good business. They are both however a pm away for a quote ( you never know, by going through lr you might get your self a little discount as a good will gesture

[Steve 90]

^^

Steve

Is it these ? :

http://www.ashcrofttransmissions.co.uk/index.php?act=viewProd&productId=253

But its not a Locker and I thought you had full lockers ?

Nige

Sorry Nige, Hadn't seen this until now. Yes its a full locker.

Can be seen here

http://www.ashcroft-transmissions.co.uk/index.php?act=viewCat&catId=89

An excellent piece of kit.

Steve.

[Range Rover Blues]

The RRC air suspension system runs at 10 bar, not sure what pressure the ARB system is but it's not that high. the EAS pump is far better than the ARB one though and is better for tyres, though it draws up to 30 amps.

TBH the system doesn't drag along the floor that way people insinuate, it's about flush with the chassis. Only thing is the way it's wired up you probably need to keep the EAS ECU to run it.

[Hybrid_From_Hell]

I think thats outstanding

11/10 to ashcrofts, that could clean up in the locker market methinks,

if my ARB pops apart again I'll prob go for one

Nige

[crispyme]

I have to say, I like the KAM kit, it is a strong and simple kit that makes it reliable. Toad and I, along with Moose as our team mate have used them hard and they have held up. But that is what you expect if you buy this kind of kit. Granted I am a bit biased as I worked for KAM

HOWEVER

The Ashcroft kit looks like a really well designed and priced piece of kit, that if I was to look for another set of lockers would think hard about not choosing the Ashcroft Locker. They have done testing and seem to have come up rosey, I would question anyone who buys an ARB.

If you are looking at using your diffs hard, the one thing I would think about is availability and cost of spares / repairs, ARB kit has to come through Devon, KAM is pretty simple and shouldn't suffer too much but if any thing does fail (not that I have known of any) most the parts aren't wallet friendly.

Hope that helps a little

Eeyore

[landybehr]

To me the intended use of the car made the difference. I am not after crawling tricky rocks, nor extreme trails/trial. In these conditions one fairly often lifts one or two wheels and then a 100% locker like ARB or Ashcroft are without alternative.

I, personally, drive off road occasionally, nothing that impresses people , but even there lockers are of benefit. Much more than offroad I conquer slippery roads, taking trailers from wet gras, face iced roads in winter and so on. All that are conditions, where I rarely ask too much of axle articulation (really, cannot recall when not at least 3 of the 4 wheels were on the ground, and therefore either the front or rear axle will try to keep moving the car; ok, if it is the rear axle lifting a wheel when travelling up a hill then I still might get stuck).

Well, for me the TrueTracs front and rear do work perfectly. I do not need to think about turning them on or off; I would be able to do so if I had ARBs, still it is nice not needing to think about them (call it comfort ). My wife will profit from their action when she drives, although she never got a briefing (which she wouldn´t want to hear anyway). The steering is not affected, even on the trail - so I get some, though not 100%, locking action offroad and still can get the car ´round corners. I believe that the action of the worm gears somewhat cushions shock loads.

I don´t argue, the TrueTrac(Torsen) were the best you can get, nor saying that 100% lockers are not worth considering. Still, for about 10years I never missed a 100% locker, but the TrueTracs served me well in a lot of situations.

[landybehr]

BTW: installation of the TrueTracs is the simplest, compared to the air/KAM lockers.

BTW: Quaife is an alternative to the TrueTracs (Could be quaife is even stronger than the TrueTracs, though I never heard them to fail. Quaife probably is more expensive)

BTW: Quaife makes a Torsenlocker for the middle differential in the LT230. Not a "must have", though. But nice.

[cackshifter]

There is more choice than the Trutrac, good though it seems to be;Ashcroft are also doing their own ATB diff, and also offer Quaife ATBs for LR axles. Quaife used to offer them also for the LT230 and Salisbury diffs.

Nigel

[landroversforever]

I do like the look of the ashcroft locker . I'm sure they will get my pennies when I come to putting a locker in the front.

[Range Rover Blues]

It was my understanbding that a Torsen is not the same thing as an ATB, that a Torsen uses worm gears in place of the planet gears (or is it the sun gears, check out the website below) such that the worm drive locks up completely. These were used in the Audi Quatro rally car and although very very good, tough etc they suffered huge backlash which worm gears are prone to. An ATB uses interlocked pairs of spur gears (unless I'm mistaken) with their axes parallel to the axis of the diff, as such they can only bias the torque (hence the name) in ratios of between 3 and 5:1.

ATB, how it works and a little light reading about torsens and ATBs (including some neat meccano models).

[Soren Frimodt]

Just ordered one of them there Ashlockers, should get it on monday. Intrigued as to what kind of kit this is, I really like the specs and the fact that it's cheaper than an ARB, have for some time been pondering whether to spend all the money on an ARB or just settle with a trutrac, but when the Ashlocker came out with such a competitive price, there where no doubt for me anymore. So far top job Ashcroft!

[Mr Ian]

Hi you are right in that the Torsen T1 is a worm and wheel arrangement, but the Torsen T2 is more like a helical gear type, Quaife,Truetrac etc this seems to be the way to go for strength. The T1 had really high bias ratios so much so they easily self destructed, we installed two of the Land Rover prototypes many years age, and broke them. The T2 has the same characteristics as the helical gear ATB approx 2 to 1, as this is a dynamic ratio no supplier will quote an exact value, needs a dynamometer both sides to vary the loads independently?? (I think). As with all things off road there are many differing needs and opinions,which is why we are offering the choice of three traction aids. The locker is self explanitary, but for further discussion on the merits of plate type v.s. gear type LSD review the notes on our web site.

Regards Ian Ashcroft

[BogMonster]

A slight thread hijack but not worth starting a new thread as it's basically the same question.

I think I may have a problem brewing with the front diff in my 110 and I suspect the diff centre is on the way out though I haven't taken it out for a look yet.

Has anybody on here got one of the Traction Master LSDs in daily use? If so what do you think of it? This one http://www.ashcrofttransmissions.co.uk/index.php?act=viewProd&productId=253

The std LR diff centre in the front diffs is a bit of a poo design and so if I have to replace it I may as well upgrade to something better. I have always fancied the Quaife design and thought that plate ones are a bit of a poor second - Dad's L200 has one and it is totally ineffective and always has been, just makes a horrible noise. On the other hand Ashcrofts are most unlikely to sell something that is a dud - so what to get...

Importantly, I don't want something that gives adverse effects in normal driving on road - most of our roads here are gravel and anything that gives funny steering effects on fast cornering is likely to increase the chances of a ditch/roof moment at some point in the future. Yes I know I could get a full locker which would be unlocked on the road but don't really want to have to find space for a compressor etc and 97% of the time I don't need a locker of any sort so this is just for a bit of extra oomph in the other 3%.

The choice is probably either to upgrade to the four pin diff centre Ashcrofts offer, or fit the Traction Master, which is a bit more expensive (£420 against £240). Comments please!

[farmerboy_y2k]

The choice is probably either to upgrade to the four pin diff centre Ashcrofts offer, or fit the Traction Master, which is a bit more expensive (£420 against £240). Comments please!

Why not a truetrac, which is cheaper than the Traction master?