LSD80% VS LSD40% M220 "Factory"

I have not found information in relation to the Limited slip differential 220 80% in the 911 of 72. I have several questions
1. In the '72 911S (oil side cover) was it an extra that was included in the original? I thought this until now but when I see the purpose sport I see that it is marked as an X. Indicating that it can be added. Until now I have thought that the limited differential slip on the 911s came from the factory ...
2. Is there a document or vehicle record where the change from 40% to 80% in LSD can be noted? How was this change noted and when was it requested? When you asked for the extras, did you tell them that 220 did you want it at 80%? In that case, how was the distinction made?
sorry for the capital letters! If an admin reads this and I can "normalize" the letter of the title I will be grateful

Attachment 553033
https://porschecarshistory.com/1972-...es-911s-914-6/

If I understand your question correctly, there was no progression on the Factory limited slip. Yes, they were available from the Factory but as options. Same with the distinction between 40 and 80% function. BTW, 80% is severe for a street car and these were usually ordered for competition. In this period you mention there were considerable variances on the transmissions including, ratios, ground vs machined gears, none-20%/-80% limited slip, and a gear driven external oil cooler. All these variables just on the trans! I hope this is helpful.

FYI, I have rebuilt dozens of factory installed LSD’s in Mag gearboxes, 69-73, 911 and 914’s, all of them without exception were set at 80%. 40% wasn’t a common setting until circa the SC’s era. And non adjustable 40% around the Carrera’s and 964’s. There might be exceptions but not in my experience.

To be clear to me. The '72 911 S's. They came from the factory with the LSD ... is this correct? I have to reread the documentation! But until now I thought so. So, were there different option numbers for a 40% LSD and another option number for 80%? Or when you asked for 911, you told the factory in what percentage you wanted it and if so. How did they differ when building them on the construction sheet? Did you target M220 even if it had a different%? Thank you both very much !!

I agree, the M220 was an option, never standard, and in the early cars was set for 80%. Even for the 73 911RS, it was an option and not always specified for the competition cars.

I see that the 220 was optional and until today ... I had thought that the factory LSD came in the S ... I don't know why. Maybe I had confused it with the stabilizers ... Thank you very much and sorry for my stupidity. Apart from that, any details about whether the build sheet record is marked if the LSD is 80 or 40?

These cars continuing to be a learning experience. I've been on the driving and building side, but no experience tearing apart the gearboxes. My XREF is from a few early 911s with LSD. Again my personal experience [over 50 early 911s- yes I'm a big crazy and not a dealer] was very few with LSD and the only one with an 80% was an RS that had been raced in previous life and was still pretty much set up biased for the track. QUITE a surprise to hear that 80% was the common LSD, but ...again.. we keep learning. It also points out that even the Factory books don't always tell the real world tales.

If the numbers aren’t rubbed off the bottom, factory installed LSD’s; 70-71 gearboxes would carry the suffix 10 (911/xx/10). 72-73 would carry the suffix 11 (915/xx/11). Later gearboxes were 12 and early chill cast Alu did not identify LSD’s

with that we would have the number but if the LSD was in another percentage to the "normal" ... How would it be known? Observing the number can you observe the% and I do not know it? Or if you asked for the LSD "Touched" there was no way to differentiate it from a normal one? The explanations said here are appreciated and "FROM MY SHORT KNOWLEDGE" I also thought that LSD came to 40% originally and that 80% was something "unusual" ...

Again all LSD’s in long hoods were 80%. If u wanted something different, u took the diff out and went into the service manuals, that outline the different locking values, and re-set it. Any numbers identifying LSD’s were only for that unit installed.

how many 911 got in 1972 LSD? Many? Few? 50? 100? Just to confirm. I have found a document in this post where he quotes LSD at 80% with the extra number m220. Until recently I had thought that "Basic" LSD was 40 ...Attachment 553826

https://www.early911sregistry.org/fo...om-ESSES/page2

Yes, this is good confirmation of the 80% nature of the LSD.
However please be careful of reading this price list. Below the 220 there are unlisted options for the 5 speed transmission, and the Sportomatic. The list does NOT indicate that there are 3 options for the LSD that include one for the Sportomatic; to my knowledge, there was never an LSD for the Sportomatic. The option for the 5 speed was an upgrade from 4 speed to 5 speed. The option for the Sportomatic was an upgrade from 4 speed to Sportomatic.

This document shows that the LSd built into that vehicle is 60%! that data ... where was it obtained? Was it noted on the sheet next to the options?
Attachment 554067

https://www.early911sregistry.org/fo...der-extensions

As delivered by the factory you would expect 80%. They can be adjusted lower than 80%. I have never heard of a factory 60% setting, so assume that has a typographical error. That car was certainly modified before delivery.

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Originally Posted by davep

As delivered by the factory you would expect 80%. They can be adjusted lower than 80%. I have never heard of a factory 60% setting, so assume that has a typographical error. That car was certainly modified before delivery.

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Thanks Davep! I will "take" it as a typographical error ... but many errors ... in many documents******not about this vehicle! I speak in general ...******! By the way, about this vehicle the 9112301179. Why was the front bumper changed? It makes you think that before it had an aspect more similar to the RS and then not. What did they rely on to make that change? Is there a historical photo of this vehicle?

Attachment 554144Attachment 554145
http://www.finecars.cc/en/detail/car/25883/index.html


http://www.finecars.cc/en/detail/car/25883/index.html
Attachment 554147

I was reading more on LSD's recently, and apparently there was a short period in 1985 & 86 where the internals of the LSD were changed and the number of friction plates was halved. These were only 40%, and far less effective than the earlier versions even when they were set up for 40%. These 85/86 LSD's became known as "snow only" LSD's due to their lack of benefits. Thereafter new designs came out that had asymmetrical ramps and thus had two slip percentage factors (for acceleration and deceleration). These new designs allow an LSD to be designed or adjusted for many different situations. Combined with engine management and suspension design these new LSD's have had a dramatic effect on lap times.
The 85/86 LSD's can now be upgraded by replacing the one pair of discs per side with 2 pair that are half thickness; this allows both 40% and 80% setups to be configured.
My understanding is that the 80% configuration was standard prior to 1985, but a 40% configuration could be requested as a special wish.

Quote:

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Originally Posted by _gonbau

Thanks Davep! I will "take" it as a typographical error ... but many errors ... in many documents******not about this vehicle! I speak in general ...******! By the way, about this vehicle the 9112301179. Why was the front bumper changed? It makes you think that before it had an aspect more similar to the RS and then not. What did they rely on to make that change? Is there a historical photo of this vehicle?
]

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You can’t assume that the marketing write up to hype a car for sale is accurate. There is no mention of the time frame between taking delivery of a ‘72S and converting it to a RS look. Certainly, the RS was already being shown to the public for the ‘73 model year but, one needs to know when the RS bits were available to customers over the counter.

Quote:

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Originally Posted by davep

Yes, this is good confirmation of the 80% nature of the LSD.
However please be careful of reading this price list. Below the 220 there are unlisted options for the 5 speed transmission, and the Sportomatic. The list does NOT indicate that there are 3 options for the LSD that include one for the Sportomatic; to my knowledge, there was never an LSD for the Sportomatic. The option for the 5 speed was an upgrade from 4 speed to 5 speed. The option for the Sportomatic was an upgrade from 4 speed to Sportomatic.

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I would say that the information from 40% to 80% is from this forum, I mean. Where I have learned about LSD has been here, now that I am clear that LSD came out at 80% of the factory ... I will look for if there is any publication that cites 40%. I investigated how LSD worked in my own way ... in a very basic way I understood that it has some "separating discs", changing these you changed the percentage ... It doesn't seem like a very complicated job but what do we know about it? To make a% change. How many hours of workshop would it take? Was it something that would change (in the case of a race car) between races?
fck traductor google

Quote:

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Originally Posted by 70SATMan

You can’t assume that the marketing write up to hype a car for sale is accurate. There is no mention of the time frame between taking delivery of a ‘72S and converting it to a RS look. Certainly, the RS was already being shown to the public for the ‘73 model year but, one needs to know when the RS bits were available to customers over the counter.

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there is another 911S that has bits from the 73RS! The one with the two grills in the back ... That 911230 ... also said it "had research pieces" from the RS. But it was never clear to me if that car was the original since I also saw another photo of a similar vehicle ...
Attachment 554209

1977
40% 220

Attachment 554233

that would be 10 before what you say Davep!


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https://www.early911sregistry.org/fo...-Numbers/page3

wow .... due to different documents I am forced to ask. How and where was the installed LSD noted or differentiated? There were no factory records of whether you equipped the LSD at what percentage was it? The percentage must be understood to be related to the year? If in a 1972 COA they tell me LSD, must I necessarily understand that it is 80% moronic? If in a 1977 COA they tell me that I have LSD, I must think that it is moronic at 40%?
Where are these data recorded if they are not present in the construction file? Regarding his image ... wow. Could you tell me where it came from? Thank you.

Sometimes those changes are documented in the yearly Service Information Booklets.

From SIB Starting in 69.

From service manual.

SIB (Service Info Book) for 70. Because they are listing part numbers, it tells me not optional, but available as spare part.

For 72, from service manual.

In 75. SIB

In 76 SIB. First mention of change in standard %.

And 76 Turbo, SIB.

Great information you have gathered Gordon. From this we can understand that both 40% and 80% LSD's were available as option M220 from 1970 and perhaps as early as 1969. I suspect that when ordering option 220 one would have to specify 40% to receive that variant. What we really need to find is the salesman's order option book to see how they were instructed in configuring the options. For example, there were a lot of paint options that are not on the color charts.

Maybe but those were part numbers, I suspect not available as options. There were lots of mechanics that could drop the axles, take off side cover, remove ring gear from diff, re-stack the plates and re-install, rather than buy a new diff. I could do that job in an hour. We do need a salesman’s order info.

Quote:

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Originally Posted by gled49

Maybe but those were part numbers, I suspect not available as options. There were lots of mechanics that could drop the axles, take off side cover, remove ring gear from diff, re-stack the plates and re-install, rather than buy a new diff. I could do that job in an hour. We do need a salesman’s order info.

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information I was looking for ... Thank you very much. Regarding the other documents ... I appreciate the information! With this I would like to investigate what the SP annotation would mean next to the gearbox number on the construction sheet. I think, it has nothing to do with the installation of the LSD but rather, with an adjustment or something similar ...
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translator thing! I mean, I know it has to do with LSD but I wanted to say that I thought it might have to do with a later% adjustment or some brand to differentiate it from something

No, SP designates limited slip. Late gearboxes had a SP paper tag glued on the top web of the diff case.

SPerrdifferential

Quote:

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Originally Posted by gled49

No, SP designates limited slip. Late gearboxes had a SP paper tag glued on the top web of the diff case.

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in my case, then, I must understand that my gearbox is late?
the vehicle left the factory on January 1, 1972

No, late is 78-79. What is the complete type# and serial # on your trans.

Quote:

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Originally Posted by gled49

No, late is 78-79. What is the complete type# and serial # on your trans.

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the only information I have about her is this (it comes from Porsche France)
and the annotation by hand of SP next to the gearbox information that comes from the porsche file ... Which in turn, the number of my gearbox has yet to be confirmed in the file document. In that file of the "porsche file" my gearbox number did not appear


Gearbox type 915/02, 5 gears Gearbox number 324597
**Data of interest ... my father said that he changed it because he scratched the 2nd or 3rd ...

Is there a document that instead of "SP" where it is located says (next to the information on the gearbox)
something else? Or in the documents that appears this inscription always appears in the same place and with the same meaning? If SP means "SPerrdifferential
"Why highlight it in the construction file? I can understand that for change or repair, but this type of thing, it would not be noted in another type of document? When repairs or changes of parts were made to a vehicle, they were noted on the same sheet of construction?

Sport Purpose 72

Attachment 555563

https://porschecarshistory.com/1972-...es-911s-914-6/

so... for the 2.4 of 1972 the LSD came in 80%? correct no? IS what I see in the documents of porsche.

I own several cars with factory installed LSD’s and all were spec’d new at 80% lock. I have personally never seen a late long hood with a 40% lock but That’s not to say it does not exist.
The 915 gearbox with LSD would receive an aluminum SD tag attached to the diff side cover from factory. Samples of the tags attached on the photo along with their LSD.

SD on the label is being translated as differential slip?... because being German etc... in the construction sheet the differential slip is designated as SP already having these letters for it SD unless you are confusing this... the Porsche called his 220 ... SD on the casing? SP on the build token. 220 the number of extra... I see too many meanings to represent the same thing... compared to 80 and 40 from the documents I have seen... 72 80% or that is my perception

I would also like to make clear a thought I have about "SP""LSD"SDifference......" in the build sheet. Observing how the porsche does its thing how many of you think that SP is referring to the extra 220 and not to something else? Why does porsche highlight the LSD as SP where the gearbox information goes but more importantly.... Why are there other vehicles that have 220 that do not have that annotation? From what can be deduced from this forum... It is understood by what they say (those who know) Sp is 220. What is this relationship due to? Where does this conclusion come from? If we look at some documents... We see a T next to the model in some vehicles "that could be ST"..... some understand that T as the T of ST others (from what I have read) as tourist delivery... If it were the latter case... why mark it there if you have a box below where to put that data I get the feeling that there are many things in Porsche that are given explanations without having things clear flush We cannot issue verdicts based on belief. Where can I support that LSD was registered as SP? Does anyone have any documents or build sheets worth reading?

Quote:

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Originally Posted by davep

SPerrdifferential

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because it would be "abbreviated" with the first two letters and not with the two "letters"... which would be SD?
SperrDifferential

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Quote:

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Originally Posted by gled49

No, SP designates limited slip. Late gearboxes had a SP paper tag glued on the top web of the diff case.

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umm that tag you show... is it the tag they named post back that said "SP"?

Attachment 574851

I put these doubts to the Archive Porsche. Not with respect to this image but with reference to the SP designation. They confirmed that SP means LSD as "it is already well known"

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Attachment 574867

BMW too had the ZF 168 Diff The only difference is with 40% you have two plain 4mm shims instead of two pairs of friction sets
40% [] would be the shims and |I a set of outer/inner friction discs
[]|I -- I|[]

|I|I -- I|I|

The late LSD's Also had a reduced number of frictions sets, but without shims. So limited to just 40%.

Herr Gonbau.
When speaking German most refer to "Sperr" (SP) in the short text Instead of saying it’s full technical description "Sperrdifferential" (SD). It’s not that complicated. It all refers to the same thing.

And a Photo of the last simplified non adjustable 40% LSD. This was also used in the 924 S1 turbo snail shell housing transmissions which are based on the 915 but with a dogleg 1st gear.

Quote:

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Originally Posted by glaverbel911

And a Photo of the last simplified non adjustable 40% LSD. This was also used in the 924 S1 turbo...

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Well, as long as Robert's putting his stash on display, here's an 80% 15-bolt ZF from a 917 transmission :-)

Attachment 574885

Jon B.
Vista, CA

That is an amazing piece Jon

I dont suppose there is any way to shoehorn it into my 915 box if I can afford the kidney and other assorted body parts for it :D

Indeed Very sexy Jon. I Have a slightly off topic tool question for you if Gonbau does not mind.
Have you ever seen this version of the P80 or VW288 backlash tool ? This has no tool number or mfg identity markings but functions well.
I have never been able to label it.
Thank you.

Well, if the dial indicator position is fixed, and it looks like it is, than the distance from the ring centerline should tell u what the application is.

Quote:

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Originally Posted by glaverbel911

I Have a slightly off topic tool question for you...

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Robert, I sent you a PM.

Jon B.
Vista, CA

I am still interested in the SP registration and in the rest of the vehicles that will carry the M220. I've asked it before and I deduce the answer. NOT all vehicles with M220 carried SP marking correct? Can someone explain why in some vehicles yes and in others no? And... what other known vehicles have a handwritten SP? I'd be interested in seeing a picture...
Attachment 581439Attachment 581440
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Attachment 581441
https://www.elferspot.com/en/car/por...-1973-1958421/

OT - would anyone have a spare 'SD" alu tag I could have ?
mine was lost somewhere between 1970 and today . . .

TIA
Dennis :)

Quote:

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Originally Posted by gled49

No, SP designates limited slip. Late gearboxes had a SP paper tag glued on the top web of the diff case.

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is there an image?

Quote:

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Originally Posted by _gonbau

wow .... due to different documents I am forced to ask. How and where was the installed LSD noted or differentiated? There were no factory records of whether you equipped the LSD at what percentage was it? The percentage must be understood to be related to the year? If in a 1972 COA they tell me LSD, must I necessarily understand that it is 80% moronic? If in a 1977 COA they tell me that I have LSD, I must think that it is moronic at 40%?
Where are these data recorded if they are not present in the construction file? Regarding his image ... wow. Could you tell me where it came from? Thank you.

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I keep wondering how the porsche differentiated between 40% and 80% LSD when mounting it in a vehicle. How did the mechanic know what LSD he was "up against"?

Quote:

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Originally Posted by gulf908

OT - would anyone have a spare 'SD" alu tag I could have ?
mine was lost somewhere between 1970 and today . . .

TIA
Dennis :)

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a plate of an LSD like this, would indicate the type of %? Does anyone have images of their plates, be it 40% or 80%?

Quote:

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Originally Posted by _gonbau

This document shows that the LSd built into that vehicle is 60%! that data ... where was it obtained? Was it noted on the sheet next to the options?
Attachment 554067

https://www.early911sregistry.org/fo...der-extensions

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Attachment 595006

How do you extract the percentage of LSD to make the COA? And how was it written down in the vehicle's construction sheet...? It may be a difficult question, but I want to put on the record here that "supposedly" the difference between "Normal" and "80%" LSD is written down somewhere.

I confess there is much interesting data about LSDs in this discussion. I was surprised about the 80% being standard configuration for the earlier 911s. One aspect of this 80 vs 40% situation I believe it actually quite simple. The early 911s didn't have a ton of torque so there wasn't much demand for a limited slip. Note the 80% information applies to "Sport Purpose" [competition] and suddenly the 80% makes perfect sense. If you missed it you may find it of interest that the factory commented to the effect that 40% worked best. It wasn't until the larger displacement 911s that a locking diff was more commonly used. A good portion of 930s came with them. I may have mentioned it before that an 80% was severe when used on the street, but that's a story unto itself. Keep having fun!

Quote:

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Originally Posted by john rice

I confess there is much interesting data about LSDs in this discussion. I was surprised about the 80% being standard configuration for the earlier 911s. One aspect of this 80 vs 40% situation I believe it actually quite simple. The early 911s didn't have a ton of torque so there wasn't much demand for a limited slip. Note the 80% information applies to "Sport Purpose" [competition] and suddenly the 80% makes perfect sense. If you missed it you may find it of interest that the factory commented to the effect that 40% worked best. It wasn't until the larger displacement 911s that a locking diff was more commonly used. A good portion of 930s came with them. I may have mentioned it before that an 80% was severe when used on the street, but that's a story unto itself. Keep having fun!

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So, having a slip of 40% in 1972 would be a clue to know if it had a more powerful engine than the "normal" one... I understand that? Seen the manual published earlier by Gled. The question remains as to how to distinguish the LSD that the factory mounts between 40% and 80%. Can someone show the coa of their vehicle equipped with 220? Censored or private? The engines that I have shown in the previous COAs. Would they all be "strong..." engines? Would these all be racing cars?
Apart from this, all the 1972 vehicles (for example) made by the factory with which LSD were they assembled? Did it depend on the engine they put in the vehicle?
and fun yes! But if we all collaborate more, maybe we will come to understand some more things about the Porsche world...

All LSD’s in the early cars were 80% into the mid 70, then they were 40% thru 84 with multi plate diffs that could be adjusted. Then in 85 they became non adjustable 40%. If you didn’t like the locking value of an early diff you would adjust it, as there were 4 or 5 different adjustment settings. Don’t try to make a mountain out of a mole hill, it wasn’t that complicated. I did a 72 ST some years ago, it had 80% diff. The LSD option was not that common, mostly special order. The dealers I worked for never ordered them for cars they were flooring, thought they were dangerous.

Quote:

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Originally Posted by gled49

All LSD’s in the early cars were 80% into the mid 70, then they were 40% thru 84 with multi plate diffs that could be adjusted. Then in 85 they became non adjustable 40%. If you didn’t like the locking value of an early diff you would adjust it, as there were 4 or 5 different adjustment settings. Don’t try to make a mountain out of a mole hill, it wasn’t that complicated. I did a 72 ST some years ago, it had 80% diff. The LSD option was not that common, mostly special order. The dealers I worked for never ordered them for cars they were flooring, thought they were dangerous.

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I have just seen this response, and it does not answer my questions. We have observed that in 1972, different LSDs with 80% and 40% could be installed. Does this mean that the factory differentiated them when installing them in the vehicles in some way?


I don't think my question is difficult to understand. While I understand that this topic might be repetitive, in this post we have seen different opinions that have been clarified with documents.


It is known that LSDs were not common, and they were usually requested if the driver wanted better vehicle performance. From my perspective, LSDs could be dangerous. In the case of our vehicle, the second owner, who had an accident, may not have been accustomed to them, leading to the loss of control. I suppose that at that time, installing an LSD was an uncommon upgrade that would have drastically changed the vehicle's handling. However, I am still wondering how the installation of the LSDs was differentiated. These questions may never be answered.
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Attachment 599285
https://porschecarshistory.com/wp-co...r%20Morgan.pdf

Do all vehicles (in 1972) with a Limited Slip Differential come with the handwritten inscription "SP" on their build sheet? I've been quite insistent on this because it seems strange to me that the inscription would be on some vehicles with the M220 and not on others. This has made me doubt, as I've expressed before, the meaning of "SP" handwritten. I've also tried to find information on how the factory installed and NOTATED on the build sheet whether it was a 40% or 80% LSD, but I couldn't find an answer. The only thing I've been told is that "SP" stands for "Sperrdifferential," and my question is... why do we know this? Where does this clarification come from? And why is it emphasized on some vehicles and not on others? Why couldn't "SP" (for example) stand for "Sportausfuhrung"?
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I have raised these questions these days directly to the Porsche Archive.
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These questions were never answered by the Porsche archive

I keep trying to find documentary evidence indicating that 'sp' was the abbreviation for 'differential slip limits.' I've seen the image of the label in this post indicating 'SD' instead of 'SP,' so I'm asking again where this explanation comes from, stating that 'SP' is an abbreviation given by the German factory, an abbreviation in German 'I understand'... Is there any document that supports what you're indicating in this post?Attachment 607859

You will find SP or SD, for SPerrDifferenzial.

I have also seen, "SPD. 40%" written on a 928 gearbox, of a very special type.

I have never seen the handwritten notation of "SD" but the explanation about the other vehicle is worth it I guess! That inscription that you mention... was it made by hand on the construction sheet or are you talking about some report that Porsche provided?

Quote:

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Originally Posted by _gonbau

I have never seen the handwritten notation of "SD" but the explanation about the other vehicle is worth it I guess! That inscription that you mention... was it made by hand on the construction sheet or are you talking about some report that Porsche provided?

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On the gearbox itself, with a pencil ;)

Any news regarding this? Would the adjustment to 40 or 80 (u 60) be made by the sports department after manufacturing, and was an LSD always installed as standard? From my point of view, I doubt it, and if I'm right, there should be something on the sheet from the assembly/construction indicating an adjustment on the LSD. In some documents, we have seen the lock percentage mentioned as a feature in some Porsche letters, so it must be referenced somewhere. Is there any information on how the adjustments for different percentages were noted? For any year, especially in 1972?
https://www.early911sregistry.org/fo...3&d=1627303934
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Does anyone know the percentage of LSD that the vehicle equipped with M491 had? Did these vehicles have LSD220 to control so much engine power? It's understood that with higher engine power, especially on the circuit, which percentage would be more interesting?
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SPerrfaktor

Over time, I have been observing how the construction sheets were made. With their order, when performing all the pending tasks on that sheet. I observe SP written by hand again and the same question comes to mind.
Why?
At the end of the vehicle's construction, when the chassis has already been worked on, the engine has been mounted, and the transmission has also been installed. Why? After that moment, when the transmission and LSD M220 (which have numbering) have already been installed along with the transmission, is SP written by hand... and M220 is underlined?
Why, when there is no more work to be done on the vehicle (it has already passed through all departments, except "one"), is that handwritten note made as if to imply that it was written after the entire assembly process and the sheet was completed. Then, according to the forum theory that SP indicates spiderdifferential/LSD, why that note, at a final moment when the vehicle has already been built?
Why highlight M220 with a black line and add SP written by hand when all the work on the transmission and limited-slip differential has already been done?
That SP note, in my opinion, does not indicate spiderdifferential but SPerrfaktor.
I don't know to whom that handwritten SP note on the construction sheet belongs. Did these vehicles pass through the sports department? Is that note made in the factory or in other vehicles? For the year '72, in my opinion, it may have been done by the sports department except Z-programm 471+491 Completed in the same place where the vehicle is produced.
These are all theories that I have based on some construction sheets that I have found, like the one Huhgg showed some time ago.
From my understanding, that SP mark indicates an adjustment work on an already installed differential in the vehicle.... Nothing to remember or forget... Everything was written down and reflected, so I would like to clarify if when they told me there was a label that said SP, it was the image that showed where it said SD. And also, I would like to know where the theory that SP is Spidderdifferential comes from since I have seen that everyone, without exception, thinks the same. I would like to know what it is based on, apart from the writings on the same transmission box...
From my perspective, "SP" is a sports adjustment.
From my perspective, "SP" indicates a 40% adjustment and is the way to differentiate them on the construction sheet when adjusting, which is not the same as assembling.
Attachment 620668Attachment 620679
Attachment 620663Attachment 620664
Attachment 620665Attachment 620666
https://pbase.com/archive_racing_por...0_0945_n126200
Attachment 620667
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From my perspective and with reference to the handwritten SP inscription, in Z-Antrag vehicles that include the M471+491 package, the SP handwritten note should not exist, as the entire process was done (I think) in the same place, where I also believe the LSD, which is part of the Antrag 471+491 package in the vehicles where it was installed, was adjusted.
Now, if this is the case for Z-Antrag vehicles concerning transmission and M220 adjustments, I would like to examine the sheets of the 21 clients from 1972 to see if this adjustment also exists in them.
or it was carried out somewhere other than where the M471+M491 vehicles were worked on.
and let all this be understood as uncertain information, because if not...
Does anyone know with which Sperrfaktor the 1972 vehicle 495 was delivered?

I did the gearbox in 495, no type number, stamped numbers only, 80% diff, special ratios and prototype style oil pump. I’ve never seen any early gearboxes with hand marking, that was later in the late 70’s & 80’s. As done with production numbers stamped in knee rail, the grease pencil markings on the dash were for quick reference. If you didn’t like the diff settings, I’m sure you would be referred to the service manuals for re-stacking the diff plates.

I thought the transmissions equipped with 220 had an stamped* inscription; perhaps these special vehicles do not. Is that what you're indicating? Is there any image in the forum of the oil pump or where it was mounted? Was the support provided by the transmission, or were there places on the chassis to fix it?
Regarding the percentage, I understand what you're saying; it was explained before. But when a vehicle (for example, M491) was to be factory-fitted with the percentage at 40%, how was that difference noted compared to the other M491s (like 495) with the percentage at 80%? I understand it's easy to adjust, but the question is about when the factory set it at 40% or 80%...or 60%...
When the employee installed the LSD, it's clear that it was always installed at 80%, right? Never at 40% from the factory? Was the LSD adjustment done by the sports department by any chance? Or could this LSD be adjusted on the assembly line? From my perspective, it was always set at 80% (standard) and then adjusted later. My theory is that this adjustment is noted as SP. But without more examples...
On another point, what would be the purpose of an LSD at 40%? Would it help to better control the engine's power? Would it make sense to install a 40% LSD on a 632XXX engine? Or would that percentage be excessive for that type of engine? The simple question is whether the 40% LSD was intended for the M491.
And thanks for your clear response.
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I found some documents that show LSD at 40% and SP notation so my theory or what was shown here in the last post. It's wrong!
Likewise, it still seems strange to me that notation by hand ONCE the transmission is already assembled.