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Post Info TOPIC: De-Myth the LSD 420/560 Rear Differential + Axle Ratio and Photos


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De-Myth the LSD 420/560 Rear Differential + Axle Ratio and Photos


MERCEDES-BENZ W126 420 and 560 DIFFERENTIAL INFORMATION-

There seems to be a lot of different opinions about the rear differential that is found in the W126 Mercedes Benz.

The first MYTH out there is that all 560's come equipped with LSD. The term LSD stands for Limited Slip Differential. This term is properly used only when a differential has clutch packs within the carrier to lock the spider gears while accelerating in a straight line.

STANDARD OPEN DIFFERENTIAL- (Most commonly found in ALL W126 Mercedes)
A rear axle must be able to differentiate or "Break Free" when the wheel on the opposite side spins at a different speed When a car makes a turn is a good example of when the tires spin at different speeds When turning the inside tire will turn slower than the other due to the physics involved. When this happens the differential is working to Break Free and applies the power to the wheel with the least amount of traction. We often call this a "One wheel peel" meaning that after a burn out you will most often times see only one tire mark on the pavement. Most all Mercedes-Benz W126 have a standard "Open differential". DO-NOT believe ANYONE who tells you otherwise. On the forum BenzWorld.org they try telling people that ALL 560 Mercedes come with a LSD differential, when in fact we have torn more apart and can tell you this myth is NOT TRUE.

LIMITED SLIP DIFFERENTIAL- aka LOCKER (Rare AMG)
The limited slip differential is one of the best rear differentials that you can own for use on the street. A limited slip differential will contain clutch packs within the housing of the carrier to keep the spider gears from "Breaking Free" while moving in a straight line and allow the unit to "Break Free" when making a turn. Hence the term POSI-TRACTION. These units are VERY rare to find in a Mercedes outside of an AMG Gleason Torsion unit. To date we have yet to see a factory made LSD differential in any W126 Mercedes produced from 1986-1991. Some LSD differentials go one step further and are considered "Lockers". These units typically have additional springs to keep the spider gears from "Breaking free" while going forward.

SPOOL-
The term for a differential that does not have spider gears is "Spool". A spool is basically just a solid carrier where as two axles connect. A spool does not "Break free" when turning and often a car with a "Spool" or the spiders welded will bark the tires when turning due to the difference in tire speeds while turning. "Spools" are not generally for use on the street due to their un-forgiving nature and the fact its entirely possible to break an axle or cause severe axle damage when trying to turn too sharply. Spools are mostly found in highly modified race vehicles only.

I hope you all find this information useful. I know on many forums getting a straight answer can be like trying to find a needle in a hay stack, but were trying to change all of that.

The gear ratio that will be found in all W126 Mercedes Benz 420 and 560's is a 2.47

The early Pre 1986 W126 Differentials will not fit on the existing sub frame of the 1986 and up Mercedes and vise versa. Keep this in mind when considering changing your differential.  
 

One other thing to consider is the ASR option on some 560 Models. I belive this is where many confused the term ASR with LSD. The ASR is a traction control system and is usually only found in the 560 Mercedes. While the gear ratio on these units are also a 2.47 they also contain an open differential. The only diffrence between the ASR rear differential and a NON-ASR is the addition of a wheel speed sensor. ASR rear ends will have TWO sensors rather than one. I have shown a photo of an ASR differential where you can clearly see two speed sensors on top, rather than the normal one sensor found on the front. 

Here are some photos of the insides and outside of late model 1986-1991 Mercedes-Benz 420/560 Differentials.



-- Edited by Administrator at 05:08, 2007-10-14

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All the best!



User

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Wow! You first real post that actually means something! I didn't know you had it in you Rex! There are a few holes in your wright up, but not bad. Their may be hope for you afterall! You see, posting stuff like this (see above) goes a lot further than acting like a complete jack ass and trying to flame people. See how this works! Well, I'm still gonna bash you because your such a jerk, but keep trying.
Regards,
MS Rocker Guy

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User

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Well really that is nothing. The REAL information jackpot is http://www.sellc.us/remote and that is where its at. This stuff here is just for people to knaw on.

As far as any holes in the above write up goes, where do you see them? I think maybe your name should be BS Rocker. The only holes here are the ones in your head! LOL


-- Edited by Stellar007 at 08:13, 2007-11-11

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Anonymous

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Can you tell me the location of the ratio tag? I am having a hard time finding even a part number for the third member.

Thanks in advance



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The tag is usually located on the back of the differential cover. If it is missing then its likely the rear end was serviced at one time and not re-insalled.

If the tag is missing you can pull off the the cover and the ratio of the gear will be stamped on the ring gear. Just spin it unitl you see the numbers indicating gear ratio.

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CERTIFIED POST WHORE

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MERCEDESSHOP ROCKS wrote:

Wow! You first real post that actually means something! I didn't know you had it in you Rex! There are a few holes in your wright up, but not bad. Their may be hope for you afterall! You see, posting stuff like this (see above) goes a lot further than acting like a complete jack ass and trying to flame people. See how this works! Well, I'm still gonna bash you because your such a jerk, but keep trying.
Regards,
MS Rocker Guy



Did anyone ever send you the memo about MercedesShop no longer being called MercedesShop? They are now called Peach Parts. I guess part sales was the sole purpose of their web forum.

It appears that you are still "Clueless" about how THIS site works.

 



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CERTIFIED POST WHORE

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Stop the press!

Some folks are saying they have proof that the W126 Mercedes does infact have a limited slip differential. While I myself have never had to tear out the spider gears, some folks have made a compelling argument backed with photos to confirm there is infact supposed to be a Limited Slip Differential in the upper class 560 models.

I may stand corrected that the 560 does offer this limited slip differential standard, however the last two we salvaged did not. Perhaps they had been replaced at one time or another, with open differentials or perhaps it may have been an option, but the fact remains that there is such an animal out there.

From what I can understand, these limited slip differentials (As shown in the photos of the 560 differential) are somewhat easy to spot. If you look at the photos above of the 560 differential, then look at the standard open differential you can see the diffrence in design. The non-limited slip "Open" differential looks, well... Open. While the Limited Slip design looks to have less access to the spider gears.

While we do not have any 560 differentials at this time that can be spared, we have plans to break one down in an effort to validate these claims. 

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Rookie

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It said in my owners manual that my 1990 560 sec comes standerd with a limited slip diff

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Yes we have found that the 560 does in-fact have a limited slip differential. Apparently the first two 560's that we had purchased for parts at one time or another must have had their LSD differentials replaced with units from a 420. Apparently these LSD units wear out causing noise when turning, and thus we have been skeptical every since then.

So the moral of the story here is this, "If you purchased your 560 used, make sure someone didn't steal your LSD unit!" LOL.

The situation was made worse when a customer from Tennessee purchased an LSD unit from one of our parts 560's only to get it and find out it was just a standard differential. It was not only embarrassing, but we lost a customer over it. The guy was a nuclear engineer too.  

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UNSTOPPABLE!

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How bout you rebuild one sometime like a real technician instead of swapping used axles around like a backyard hack?

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I am sorry PowerStroker, do you own a Mercedes?

No? Well then I suggest that you shut that hole in your head.

I have never had to pay out of pocket for a single brand new Mercedes-Benz part outside of oil, gas, guides ($15), Gaskets ($40) and filters in the 10 years that I have owned one and I am quite proud of that fact.

I realize that one day I will have to break down and buy some rubber based parts and maybe some other "wear" items, but I'll cross that bridge when I get there.

I should also mention that many of the parts found in a Mercedes-Benz rear differential (It's not an axle you idiot) are more expensive brand new than the vehicle you drive every day.

You should also know that I have been building up a nice core stash of Differentials, Gear Boxes, Transmissions and Engines so that when the time comes I can rebuild them. As it stands Mercedes-Benz is not like the Fords that you are used to owning/repairing, as Mercedes were built to last, not to become Obsolete in 2-3 years like a Ford.

So... Have a nice day!

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UNSTOPPABLE!

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SELLC wrote:

I have never had to pay out of pocket for a single brand new Mercedes-Benz part outside of oil, gas, guides ($15), Gaskets ($40) and filters in the 10 years that I have owned one and I am quite proud of that fact.

But how much have you paid over the years to acquire used Mercedes vehicles to harvest for their used parts???

I should also mention that many of the parts found in a Mercedes-Benz rear differential (It's not an axle you idiot) are more expensive brand new than the vehicle you drive every day.

Maybe Mercedes does that on purpose to prevent riff-raff like you from driving their vehicles, they have an image to maintain after all.

You should also know that I have been building up a nice core stash of Differentials, Gear Boxes, Transmissions and Engines so that when the time comes I can rebuild them.

You should know that I have been building up a nice core stash of tools and skills to repair things when they break down, so that when the time comes I can actually fix what's broken instead of swapping out entire assemblies.  My method also saves on storage space.

As it stands Mercedes-Benz is not like the Fords that you are used to owning/repairing, as Mercedes were built to last, not to become Obsolete in 2-3 years like a Ford.

If what you say is true, there would be no need for you to stockpile their parts.

So... Have a nice day!

likewise


 



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"If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you."     Lyndon B. Johnson

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PowerStroker wrote:

 


But how much have you paid over the years to acquire used Mercedes vehicles to harvest for their used parts???

Let's just say my Mercedes have paid ME to drive them thru the years.


Maybe Mercedes does that on purpose to prevent riff-raff like you from driving their vehicles, they have an image to maintain after all.

Nope, it just goes with the territory on an $80,000 automobile. I should also mention that Mercedes still offers replacement parts on vehicles older than 20 years! Yep that's right PowerStoker, unlike Ford and GM, Mercedes Benz actually supports their vehicles past 8 years, unlike a Ford or GM where as they quit offering replacement parts from the manufacture. Shot yourself in the foot again, huh PowerStroker?

You should know that I have been building up a nice core stash of tools and skills to repair things when they break down, so that when the time comes I can actually fix what's broken instead of swapping out entire assemblies.  My method also saves on storage space.

Yes I have been building up a nice stash of tools and skills also PowerStroker. So it seems I have you beat! Tell us all PowerStroker how often the dealer or manufacture actually pays YOU to rebuild an Engine, Transmission or Rear Differential? Or do they usually supply you with a factory remanufactured unit and pay you to install it? Yeah that's what I thought! Tell us all when the last time was that the dealer paid you to rebuild an entire engine, transmission or differential? Answer is... NEVER! aww

If what you say is true, there would be no need for you to stockpile their parts.

Well let's face it, if Mercedes parts went bad as often as Ford parts, I wouldn't have a "Stockpile" now would I? You know what manufacturers I can't keep in stock to save my life? Ford's and GM's! Every truck, Mustang or Camaro I have ever cut up sold just about everything in no time. I literally have NOTHING in stock for any of the above mentioned GM and FORD vehicles (thats not already spoken for), and trust that I have cut up just as many if not more of them combined thru the years. What does that tell you? Yeah I know what you will say, something about a strong demand, but would there really be a demand if the original parts stood the test of time? I doubt it.

So... Have a nice day!

likewise


 




 



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UNSTOPPABLE!

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SELLC wrote:
Tell us all PowerStroker how often the dealer or manufacture actually pays YOU to rebuild an Engine, Transmission or Rear Differential? Or do they usually supply you with a factory remanufactured unit and pay you to install it? Yeah that's what I thought! Tell us all when the last time was that the dealer paid you to rebuild an entire engine, transmission or differential?

Well Rex, in terms of rebuilding an engine from scratch, that is not frequently done under warranty.  The reason is Ford would rather send us a reman short or long block because it is cheaper for them to pay their people to rebuild them, than to pay one of their franchise dealers a hundred bucks an hour to do so.  That doesn't mean we don't do any internal engine work, we do.  As the Diesel specialist at my dealer, I find I am usually able to save an engine in most cases by repairing what's wrong.  If it needs head gaskets - it gets head gaskets.  If it needs a head, it gets a reman head.  If I have a melted piston and the cylinder walls aren't too bad, I will actually hone out that cylinder and replace a piston under warranty.  If however it is seized or has severe damage that would require boring - then it would get a reman short block.

In terms of transmissions they are almost always rebuilt by our trans techs.  unless the damage is so catastrophic that repairing it by anyone would cost more than a new one.  Transmissions are more cost effective under warranty to have them rebuilt by the dealer techs because aside from some occasional servo bore repairs, there really aren't any specialized machining process required.  Sometimes our transmission guys will even replace a transmission case and transfer all internal components to the new one.  And rarely do they ever throw an entire rebuild kit in one under warranty - they actually diagnose which part of it failed and repair that part only.

Differentials are almost always rebuilt at the dealership too, except in rare cases where the housing may be damaged.  We regularly do ring and pinion sets to resolve pinion whine.  Also a common repair is replacing limited slip clutch packs and carrier and pinion bearings and races for growling. 

So me personally, I do a lot of internal engine work - especially on Diesels.  I also rebuild differentials.  Transmission work though will be done by a different technician who specializes in them.  By the same token, those trans techs wouldn't be caught dead with a repair order for a Diesel concern.


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"If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you."     Lyndon B. Johnson

BLACK LIVES MATTER



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So in a nut shell, NO you do not overhaul engines on a regular basis, and NO you do not do transmission work.

I DO overhaul engines, I DO NOT do transmissions, however I plan on a full overhaul on several of my (4) stock-piled transmissions. These are not customer pay, however depending on how mine works out I might offer the service.

I have also replaced my share of carrier and pinion bearings, as well as ring and pinion and differential (most of them LSD) swaps. 

I have never had a Mercedes Benz rear differential go out on me, or start to make noises while turning. The only problems I have had is finding that some punk stole the LSD differential out of my 560 somewhere down the line and replaced it with a standard unit from a 420. Most people coming to me looking for a 560 differential are doing so for the LSD feature.

Back in the day people on BenzWorld.org claimed that ALL V8 W126's had limited slip units, however I found that to be false. While it is true that a 560 Mercedes SHOULD have an LSD unit, there are a great many of them out there that have had their LSD units stolen, and thus anyone thinking that just because they had a 560 meant they had the LSD option could be in for a surprise. 

Mercedes does their LSD units differently than what you would find on a GM or Ford. The clutches are not visable and there is no S clip in the center like most others. If you look at my photos in the first thread, the one that says "560 Diff" is in fact a 560 LSD unit, the other one that is shown without any writing is the standard open diff found in most everything else (300 - 380 and 420). Look close, you will see the difference, but what you wont see are the clutch packs.  



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Member

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Indeed all US-model 560SEC, 560SEL and 560SL cars with the 2.47 rear end did include LSD from the factory. I can confirm this.

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Not true Gerry...

I been holding this back from the guys a BenzWorld.org because they always like to steal my info, but Ill let you in on a little secret.

Do the ASR equipped 560's have LSD Gerry? No they dont. So the myth that all 560's have the LSD rear end is not true.

I have also learned the hard way that while all NON-ASR 560's have a LSD from the FACTORY that does not mean that by the time a 2nd, 3rd, or 4th owner buy them the LSD unit will still be in there. I have purchased a few 560's only to find they have been replaced at some point with 420 rear ends. The LSD rear ends get noisy when they wear out and sometimes places will stuff a 420 unit in there because they cost less.

So the old saying on BenzWorld.org that ALL 560's have an LSD is not true.



-- Edited by SELLC on Saturday 27th of August 2011 03:20:28 AM

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You are indeed correct with that exception of the 1991-only 560s with ASR not having factory LSD.

I should have been more specific with regard to this small subset of one out of the 6 years' production of 560 models.

It is definitely also true that over time and mileage (not to mention as you say if the rear end was replaced or monkeyed with) that the factory LSD wears out and effectively stops working, in some cases a non-appropriate pumpkin being installed.

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I was just wondering ... what the F is PowerStroker doing in this forum, anyway ?

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My 1987 560 SEC was built with a form of limited slip, and has the tag that informs to only use limited slip oil. However it does not seem to work. Does anyone have experience rebuilding one?

Mercedes and Ford are two very different animals... but the bickering just wastes peoples time

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If your Limited Slip is not working anymore it's probably because the friction discs are worn out. The job is complicated and involves the entire differential housing and all to be removed. This includes the axles and the drive-shaft.

From there you have to remove the bearing caps on either side of the differential. Once out you have to disassemble and replace the discs. Assembly is a matter of keeping your existing shims in order, otherwise you will be spending some time re-setting it. It still pays to check the unit with a dial indicator both before and after.

With regards to Mercedes and Fords being whole different animals... It's only a different way of doing the exact same thing. I think you need to crawl under a newer Ford Escape and check out the differential and rear suspension, then come back here and tell me Fords and Mercedes are two different animals. 

Now who's bickering? 



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FAR BEYOND DRIVEN

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Yo People,

Remember this when checking the contact patch of the gear-wheel to crown-wheel mesh...Should you need to adjust anything...
Face or Flank, move the crank...
Toe and Heel, move the wheel...

Cheers,

Rastus

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