Yes, I suspected that's what you were talking about Dan.
If the LSD uses friction clutches to proportion torque, it's an LSD. Yes, it can be shimmed up very tight until it's effectively locked and it will skip and stutter on tight turns etc, but as you point out, the amount of traction and torque applied will determine whether it can slip or differentiate under load. That's the nature of a limited slip diff.
An auto locker does not rely on friction between clutch packs and will remain locked regardless of the amount of load applied, because an axle can't underspeed the crown wheel under any circumstances. An axle will break before it can underspeed the crown wheel. that is NOT a limited slip diff and isn't a characteristic of a limited slip diff.
The way that increased drive torque applies force to the clutch packs is the same as an auto locker, the difference is that an auto locker doesn't rely on friction, it's a dog clutch and is to positively, 100% engaged and can't disengage or slip at all. it also rests in the locked position, which is the point where D3ceptikon and I disagree - he believes in the absence of drive load the diff isn't in the locked position, I believe it is.
An LSD of the type you describe won't display negative handling traits until it's shimmed up tight (which you may want to do for competition etc) but it also won't generally drive the car up a hill with one wheel on that axle in the air while the wheel with traction is up against an obstacle. That's because if the coefficient of friction of the clutch on the loaded wheel is insufficient to drive that wheel, the diff turns back into a regular open differential. An auto locker can't do this as it no longer has spider gears.
The lack of negative handling traits is why clutch LSD's are common in factory applications.
I offroad applications clutch LSD's are unpopular because by the time they are tight enough to drive the carp an obstacle on one wheel, the handle poorly and you might as well have a locker.
That's because LSD's are designed for surfaces where both wheels have similar traction levels and the LSD is there to counter weight transfer The old trick with toyota clutch LSD's would be to apply the handbrake when one wheel was in the air. This would have the effect of balancing torque slightly across both wheels and LSD would grab a little.
The way that increased drive torque applies force to the clutch packs is the same as an auto locker,
finally, thank you.
Gwagensteve wrote:
the difference is that an auto locker doesn't rely on friction
once again, you are incorrect. from about the 2 min mark of the vid i posted earlier, looking at the vid where the two halves are together you can see that the dogs are not at 90 degrees to the face but they are at a slight angle which, while no other forces are applied, leads them to be pushed apart and thus this can not be called "locked"
here is another pic of it showing it more clearly
and again at the 3:50 point in the vid i posted he explains that the teeth are "slightly bevelled" which is what enables them to ratchet.
it is, in fact, the friction that is caused by these dogs that "limits" any "slip"
where the "lock" comes in to one of these lockers is when the shaft applies more force to the dogs angled faces can be overcome by a lack of friction, stopping their tendency to slip/ratchet
understand it yet? if not ill take it a step further back and explain to you how again
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it also rests in the locked position, which is the point where D3ceptikon and I disagree - he believes in the absence of drive load the diff isn't in the locked position, I believe it is.
and again, unfortunately you are incorrect and deceptikon is in fact absolutely correct as per my explanation above.
go back and watch that vid i posted, watch it closely and without your already pre formed biases and judgements and it clearly explains it perfectly. again the part around the 3:50 mark explains it perfectly to help you understand what is going on.
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An LSD of the type you describe won't display negative handling traits until it's shimmed up tight
actually they do, try making a right hand turn into a side street in an industrial area or where there is dirt on the road or something and when you accelerate to turn into the street you will find you are still travelling up the road in a straight line..... quite a shock when you arent ready for it. they will also do the same when you accelerate to do a sharp u turn because as you apply forward pressure on the diff they lock up and the diff binds up until you reach either the limit of grip on a wheel or something breaks just like driving a full spool... this is all without having them shimmed up, this is exactly how a mechanical LSD is designed to work (and why, for a time, they were illegal in street cars over here, same as spools are here) the more power you apply the more they lock up.
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but it also won't generally drive the car up a hill with one wheel on that axle in the air while the wheel with traction is up against an obstacle. That's because if the coefficient of friction of the clutch on the loaded wheel is insufficient to drive that wheel, the diff turns back into a regular open differential.
again you are completely wrong and driving a lowered car with extremely stiffly sprung suspension its not unusual to get beached on things like driveways with one rear wheel waiving around in the air. the way to get over the "obstacle" (being the kerb/driveway in this instance) is to basically drop the clutch, forcing the shaft to lock the diff and powering you up while you only have one wheel on the ground. the other way is to apply brakes which will again apply enough friction on the raised wheel, locking the diff and getting you out of trouble. as i said i have had to do this countless times in mine.
hopefully im getting somewhere and you are beginning to understand....
I offroad applications clutch LSD's are unpopular because by the time they are tight enough to drive the carp an obstacle on one wheel, the handle poorly and you might as well have a locker.
That's because LSD's are designed for surfaces where both wheels have similar traction levels and the LSD is there to counter weight transfer The old trick with toyota clutch LSD's would be to apply the handbrake when one wheel was in the air. This would have the effect of balancing torque slightly across both wheels and LSD would grab a little.
while this is true about a normal LSD it is untrue about a mechanical lsd which is why they are preferred for things like racing applications. they handle like a spool when its needed and handle like a normal lsd at other times. this means when you are turning into a corner you can have the diff loose which aids in turn in but make it lock on exits giving the most traction to the wheel with the most grip. this is why 1 way and 1.5 way lsd's exist. 2 ways are more for the drift kiddys who also want lock on decel to get that lovely long pre entry slides into corners well before the corner without having to rely on the handbrake.
the handbrake trick is what i wrote in my previous reply, works even better with a mech lsd.
but all this aside, this began when i tried to give my opinion on different diff oils working differently in diffs, helping combat the clunking in diffs and you have offered zero explanation for why you had to pipe in and "explain" how different/similar the 2 diff types are and every time you have tried to "explain" why the diffs are "nothing alike" it still goes zero to expliin why a different oil could not help the situation?
Dan` wrote:
i found that in the nissans the mechanical lsd'd (which i assume are very similar to the lockers) the type of oil made a massive difference in the bangs (in several different brands of centers, nismo, cusco, i forget the other brand ive worked on). i forget which brand of oil it was now but i know it when i see the bottle, will try and remember to go have a look.
Gwagensteve wrote:
The Nissan mechanical LSD is nothing like an auto locker.
Because an auto locker does not rely on clutch pack friction.
indeed, it relies on the friction created in the dogs
Quote:
We're clearly not going to change one another's minds on this.
because the facts do not lie and you have done zero to explain how your theory can overcome the laws of friction and leverage. "it is the way i say it is because i say so" is not an explanation that anyone should pay any attention to.....
You think I don't understand how these centres work. I completely and fully understand how they work. Stop trying to convince me how they work. They're not complicated.
The issue is "are they locked in a rest state" and the answer is that they are, and this photo proves it.
This is a locked auto locker
As is this
and this
A couple of weeks ago I was able to find a photo of one unlocked. I can't find it now.
How "loaded" the mechanism is isn't relevant. If it's transferring no torque there's no load on the couplers, sure, but that doesn't mean it's not locked.
I'm sure some oils will limit the noise less than others.
You think I don't understand how these centres work.
i KNOW you dont understand how htey work, you have "faith" that you "believe" they work a certain way even in the face of obvious proof to the contrary. if you watched that vid i linked you can SEE for yourself that when he has the parts in his hands they are not "magically locked" by some imaginary force. and as i have explained before, the angle of the teeth prove that they are NOT locked but have the ability to move/slip/ratchet.
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Stop trying to convince me how they work.
im not doing anything but pointing out the facts.... and you seem to be oblivious to them. im not trying to "convince" you of anything.
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They're not complicated.
too complicated for some so it seems....
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The issue is "are they locked in a rest state" and the answer is that they are
as i have already explained to you, and is clearly shown in the vid, without the pinion shaft pressing on the locker the locker is FREE TO RATCHET!!!!!!! so it is NOT locked...
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and this photo proves it.
BWAHAHAHAHAHAHAA you have done it agian....... "it is the way i say it is because i say so".... or in this case "it is the way i say it is because these random pics that tell me nothing" your pics, with zero explanation of how they prove you point is meaningless and hardly more compelling then a video showing you EXACTLY how they work/move....
Quote:
How "loaded" the mechanism is isn't relevant. If it's transferring no torque there's no load on the couplers, sure, but that doesn't mean it's not locked.
/me sigh. let me try agian....
see how the sloped sides allow it to "ratchet" around? in an auto locker you dont just have one side sloped but you have BOTH sides sloped (all be it on a much steeper angle, but not 90deg) which is what enables them to ratchet around. when the latch is at the bottom of the ratchet cycle its not "locked" there because with enough force you can still turn the wheel and it will ratchet to the next drop off.
Quote:
I'm sure some oils will limit the noise less than others.
so, finally we are back to what i originally said... and you agree with me... without showing how little you understand about the workings of a diff....
i thought it was common knowledge they were locked & 'unlocked' when turning etc. a lot of guys say they should be called auto un-lockers.
that would be incorrect because they only lock once the pinion shaft pushes against the centre. once again if you go back and watch the vid i posted he clearly demonstrates that the shaft hole is not round but is ovaled out which is how the pinion shaft applies its pressure to the dogs to keep the diff locked. if you made the centre hole square so the pinion shaft was pressing against a flat surface rather than a round one the locker would not lock at all. go back to my other vid explaining the difference between 1, 1.5 and 2 way diffs for a better explanation of what i mean.
Wheel can be turned easily by hand to overcome the little springs on the clutch mechanism.................................Steve still convinced that they are always locked..................................
Keep going guys... no really, keep going. You can keep explaining to me how they work, which I fully understand, and Il'l keep showing you photos of the lockers with the teeth engaged in the locked position, of which there are hundreds and hundreds of photos. This could go on for ever. I promise you I won't get bored.
how on earth does a static pic show you that something is somehow locked? your incredible mate... boldly going where no intelligent life form has ever gone before....
what you have literally done is said that "this pic proves that its locked, because in the picture its not moving"
congratulations, you have taken stupid to a whole new level and managed to sustain it to the fullest. thats some feat
Keep going guys... no really, keep going. You can keep explaining to me how they work, which I fully understand, and Il'l keep showing you photos of the lockers with the teeth engaged in the locked position, of which there are hundreds and hundreds of photos. This could go on for ever. I promise you I won't get bored.
Ha, I'll keep showing you photos! That's what you bring to the table. Go do a course in differential repairs (and complete it), do some work experience at a local 4WD garage, tell them about your 'Unlocker' and then come back and have some input.
You've been incorrect on so many occasions on this forum it's not funny. You posted things as fact, and even I have had to correct you on a few occasions. I cant imagine all the other 'facts' on here that haven't been corrected.
myself and DC3 have facts and demonstrated proof not opinions and faith. they are completely differnt things, in fact they are opposite things. you have not proved even a single thing you have claimed and if you can not demonstrate them without them being disproven all it is is just an uninformed opinion.
I've disagreed with you. That's based on my experience. I have a bit of it. I guess that means my "facts" are different to your facts.
Do carry on.
Steve fact - Jimny - The temperature is measured in the engine coolant, not the transmission fluid. Fact fact - The fluid temp is measured under the valve body in the pan by an auto trans fluid temp sensor.
Steve fact - Jimny - the trans is controlled by the jimny ecu. Fact fact - The Jimny trans has its own separate TCM and is controlled by it.
Steve fact - I do not believe transmission temperature is monitored as part of OBDII in a jimny Fact fact - The transmission fluid temperature can be seen through ODBII and scan tool. Fluid temp, solenoids, T/C lock, vehicle speed etc can all be viewed. The vehicle has a separate Trans Control Module.
Only a few 'facts' that came to mind. There is only one type of fact Fella!
If I have a few spares years, and I'm bored as hell I will go through the rest of the posts.
im actually not sure if you guys are trolls or being serious
i assume that is aimed partly at me, if you can find a flaw in anything i have said by all means point it out, preferably with examples (but not just static pics which seem to show nothing). im happy to admit im wrong if anyone ever proves me wrong and i will happily admit i do not know everything.
edit: fwiw ive had my current GTI drover for over 15 years now and at the time i was the only person id ever heard of to fit a GTI to a sierra, in fact in the GTI conversion thread im pretty sure that using the charade thermo would have originally come from me because just before i did the gti swap i did a twin cam swap into a g11 charade and had the old g11 thermo laying around which was why i used it. i also have a jap spec imported jimni (same as sierra but with the massive turbo 660cc donk) which ive had probably 10 years and ive just bought myself a coily a couple of weeks ago which is why im here, to not only learn but to share my experience. before that i had a 1L sierra for years through the 90's. im certainly not here to troll, just to share. ive worked in and around importing, racing, rallying, compliancing, ADR stuff and all manner of things over my years and have a ton of experience in all kinds of things.
Joined: Wed Apr 03, 2013 9:37 pm Posts: 50 Location: Darwin
Vehicle: 1995 Sierra
Posted: Sat Mar 26, 2016 9:05 pm
at the risk of sounding like a prick im a mechanical engineer by trade, and ive been messing around with 4wd's since i was a kid. the auto locker is something i never really considered seriously in previous cars but i decided they were the best compromise in a cheap sierra. what gwagen is saying is that auto lockers are locked across the axle at rest, which they are, you have to apply to torque to disengage or 'unlock' them (however like i said before one wheel is always engaged.) The pictures he posted do show the differential is locked, both clutches are engaged and therefore both axles are 'locked'. the operation is not the same as an unlocked differential.
at the risk of sounding like a prick im a mechanical engineer by trade, and ive been messing around with 4wd's since i was a kid. the auto locker is something i never really considered seriously in previous cars but i decided they were the best compromise in a cheap sierra. what gwagen is saying is that auto lockers are locked across the axle at rest, which they are, you have to apply to torque to disengage or 'unlock' them (however like i said before one wheel is always engaged.) The pictures he posted do show the differential is locked, both clutches are engaged and therefore both axles are 'locked'. the operation is not the same as an unlocked differential.
The coupler resting against the cam with tiny springs does not equal locked. It can be turned and ratcheted by hand, how the hell you guys consider that locked is beyond any rational thinking.
Make sure you keep the context of the posts. I've been on here for seven years, you'll get loads of examples of how clueless I am.
I'd suggest starting with my build thread - I tend to be very blatant about all the mistakes I've made in there. You can have a jolly old time reminding everyone where I've explained my mistakes.
I was on outers for years and years before here though - make sure you get on there - you'll find NO END of nonsense I've spouted. Thats should keep you going for a fair while.
In the meantime though, here's a photo for you - An UNLOCKED lock right... UNPOSSIBLE! hang on, does that mean some guy turned the axle on that side so it oversped the crown wheel and unlocked? No, surely not!
oh, and back on topic, i think its penrite LSD oil i used to use. its quite vividly green/blue coloured oil. i still need to find an old bottle to double check... this post is more of a reminder to myself than it is to help anyone else here tho if anyone else has used penrite and its green/blue and can confirm or deny that it makes a locker better or worse ill settle for that.
its not the friction modifiers that made the difference, for some reason even other friction modified LSD oils still made the mechanicals knock at various levels of unhealthy. for some reason the oil that i used (that i still need to be sure of before i claim such) in every mechanical completely eliminated the clunking. even the recommended oils (specifically the extremely expensive nismo oils) worked no better and made it sound worse.
im still not claiming that the oil ive used in countless mech LSD's will be the cure all for lockers, but just in my experience its worked wonders where it shouldn't have, in many hundreds of diffs... and it would be a very good experiment to see if that carries over to a mech locker... which was all i was trying to point out in my original post on here that you shitcanned........
My sides haha, best read in ages, congrats to steve for keeping up the persistence. You other two are either the slowest people on auszookers or the best trolls.
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tho if anyone else has used penrite and its green/blue and can confirm or deny that it makes a locker better or worse ill settle for that.