I just got the 85w90 at the dealer. I was not about to skimp on a $900 differential.
Some dealers have the 75w85 and MB had a release that it can be used and increase
fuel efficiency. I stuck with the 85w90 because I have a 4matic and I really doubt the
mileage increase would be all that significant on a 4matic.

It has been debated here before, but the shear strength of the wrong viscosity will shorten
the lifespan of a diff.

 

As long as you are getting the 90 viscosity when you need it (hot) then the 75 probably does help fuel economy when cold.

 

There is lot of myths about oils. The viscosity is not parallel with mentioned shear strength.
Than in the case of motor oils, the low cold viscosity actually helps to protect the engine by starting the lubrication on cold start up much faster than the heavy oil, that keeps engine running with no oil pressure for long time.
If the lower viscosity oil is MB approved - I would use it unless I would live in Mojave, or similar location.
New oils, especially synthetics give much better protection, than the old oils even if you drop few points on viscosity level.

 

The only approved gear oil I know that is below 80w90 weight for the W211 rear diff is
the MB 75w85 PN 001989330312.

I am not saying others won't work, but I am sticking to the book on fluid specs for our MBs.

 

SAE J306 gear oil specs

Here's the SAE J306 spec for gear oils which backs up what Kajtek1 mentioned.

Regards,
paul...

 

Yes, you can use Mobil1 75W90, in fact will give you mor protection at working temp, because your W211 has factory installed 75W85. See attachment!!!

 

I would pony up for the MB 75w85. The Mobil 1 does not have an MB spec.
You will make the money back on better fuel mileage being that is an 85 and not 90 weight oil.
Part #001 989 3303 12

 

If MB uses 75W85 or 85W90, I think that using Mobil 75W90 covers both MB products. May be Mobil1 Gear Oil is not approved for now by MB, but will be in a future. Every time when I open the hood, I see label "MB APPROVES MOBIL1". Mobil1 engine and transmission oils are been approved for long by MB and it is going to be a matter of time that gear oil label to say, "Meets MB 235.7 Spec". By the way, some other company make MB's oils for them, which they sell to people not thinking enough and willing to pay extra for MB brand oil or grease. Every car manufacturing company does this, they will tell you that you have to use their products otherwise you may have problems - it is about profit. Why MB does not make cars like the ones from 70 and early 80, because once you buy they do not see you except for oils and tires, if you go back to them. That is why over 75% of the cabs in Germany were MB E class, not anymore since the stupid merge w/Chrysler group may be in the future this will change again. My dad was a truck driver. He was saying that MB trucks are like a mule - they keep on going with less maintenance forever and you still can see many of old ones from 50 to late 70 running in Africa and Asia. Even the new ones are that way, but not the cars. Why do you thing they change engine oil on those trucks every 90 000 - 100 000 miles (not kidding look the attachment), but on the cars is 10 000 miles - PROFIT, that is why. MB cat is not average JOE's car that why they expect most of the owners to go back and make profit from them, but if you buy truck for business is a different story, and they want you to be happy, otherwise you will buy something else next time. Statistically 90% of the people who own MB go and buy MB next time again, because MB is a name associated with prestige and you want to keep the image you build.
At the end, it is your money and you spend them the way you want. Do not say to someone "do not use this oil, or go and dump the oil which you just putt, because the label does not say "APPROVED BY MB". Look at the facts, thing and then make decision, INFORMED DECISION, as we say in the medical field. Gave the people something that they can see, do not just say MB approval# or part# then they can chose what to do. Those forums are to help people when they have problems, or want to know something in advance, instead I see too much TALK w/o saying anything. I PM to couple of members asking something and guess, they never answer. I think that they run in some problems that I try to avoid asking upfront, but they will not share.
:surrender:

 

I know MB has their fluids re-branded. I also get them at wholesale so I understand people trying
to save money. I believe Wolfgang's ML page had the same test/list.
There was a test posted at the ML Outpost about shear strength under heat and load and
the Mobil 1 75w90 did not pass the test. Maybe the new stuff is better, but IMO the risk
is not worth it.

 

Mobil 1 75w90 FAILS the requirements of the MB differential.

The 75w90 70% thinner and does not meet the minimum requirements for the differentials.

Synthetic Mobil 1 Differential fluids:
75w90 = 106 cSt
80w90 = 136 cSt
85w90 = 153 cSt

NEVER use a 75w90 when 85w90 is called for.

 

Since 2001 all E class cars are factory fill w/75W85, no one calls for 80W90 even MB states that 75W85 can be used on previous models which call for 80W90 or 85W90, look at the attachment (tired of posting same things).

 

Thanks DB, I was going to search for those numbers you have posted many times before.
It just is not worth trying to save a few dollars on the fluid that can ruin a $900 part.

 

My owner's manual calls for the 85w90. Is that because it is a 4matic?

Also I am aware of the 75w85 and agree that the MB fluid made for them by Fuchs is what
has been referred to in a MB service DTB. However I won't pit the the Mobil 1 in 75w90
in for reasons already listed and the warranty I have.

 

85W90 for the transfer case.
Fuchs oil has lower cSt at 40°C DIN 51562-1 81.5 mm²/s and Mobil has 106 at same temperature. Mobil Delvac Synthetic Gear Oil has MB 235.8 approval with cSt at 40°C of 120, so Mobil1 Synthetic Gear Oil, which differs slightly, and stay between Delvac and Fuchs would meet MB requirements for gear oils 235.7.:dunno::dunno:

 

MB does not permit the use of anything less than 85w90 for US Spec cars.
(I hate repeating myself)

Straight from the US Spec manuals...

Rear differential:
1.06 US qt (1.0 l) Hypoid gear oil SAE 85 W 90
E 350
E 350 4MATIC
E 320 CDI
E 500
E 500 4MATIC
E 55 AMG*
*(MB Hypoid Gear Oil (85W-90)
MB Part No. A001 989 28 03 10)

Front Differential:
0.63 US qt (0.6 l) Hypoid gear oil SAE 85 W 90
E 350 4MATIC
E 500 4MATIC

Transfer Case:
0.62 US qt (0.585 l) MB Transfer Case Fluid
E 350 4MATIC
E 500 4MATIC

And wait they get thicker yet!
Hypoid Gear Oil
SL65 AMG (all model variants)
E63, SL55 AMG, CLS55 AMG, and CLS63
AMG equipped with AMG Performance
Package only
For rear axle differentials
Castrol SAF-XJ (75W-140)

 

This is a b*** s**** my CDI diff takes 1.3L and it is based on the gear diameter if you do not know some are 2.62 ratio some are 3.07. in addition, I hate to repeat myself too. Some people are like donkey on wire bridge, they read something once and that is, not going any further. One of the images I posted is from Star Service DVD for W211. I will repost again, just take you time to look the attachment before start your reply. In addition, it says that all cars are factory-prefilled w/75W85 synthetic oil. I just came back from MB Service department. I ask them if I can buy FUCHS differential oil (75W85) and they ask me for what car is it. Guy check and told me that needs to be order (55$ for a bottle). Hi also offer me Valvoline SYN power full synthetic oil (75W90) 14.95$ what they are using for fill ups or topping. After this I talk to the Service Department Manager about the oil viscosity and he say that any synthetic oil that meets meet API service MT-1/GL-5 EP requirements, can be used if viscosity ranges are been meet.

 

I recently did the fluid on my transfer case and it was an ATF type fluid that was tinted
a light brown in color. MB part # 001 989 23 03 10. It is the only fluid the dealers are
putting in the W211 gasssers. It can be purchased in 1 or 5 liter bottles. No gear lube
is supposed to go in the transfer cases.
On the ML 430 the transfer case uses approved Mercon III ATF and in that I did use Mobil 1.

 

HI! Everyone

Thank you for the replies....
Finally I ordered OEM oil at

Your Parts Search Returned 1 Part(s)

1 liter $28.31

I called dealer and Dealer gave me a $ 36.00+tax(9.75%)

 

Wow, that is a pricey dealer. Mine listed it of $27.13 and sold it to me for $23, but the
good news is you got some great fluid to keep the diff happy for years.

 

This is for syn fuchs75W85 not the conventional 85W90

 

I believe so, they will both work and are blessed by MB. I just stuck with what the owners manual said.

 

I am running Mobil1 75W90 full synthetic.

 

Don't confuse the specs with Viscosity.

Because of varying climates that these cars are sold in MB WILL require for certain regions a high viscosity range WHILE requiring compliance with a certain specification. Also certain regions will have different components that may/will require different viscosity ranges.

In the US the first and most important specification is the viscosity range THAT complies with the MB 235.0 and MB235.7 technical standards. Yes there are thinner fluids that comply however those fluids ARE NOT permitted for use in specific regions and specific applications.

Again in the US markets nothing thinner than 85w90 may be used that complies with MB235.0 and 235.7 standards.

 

85w90 is a synthetic...it is produced by Mobil/BP/Castrol for Mercedes List is around $30 per liter, if they cut a deal it can be had for around $26.00. This is a high end synthetic not a conventional lube which is why MB is using it on more and more applications becuase of its better protection to the differentials.

In the US we pay about 1/2 the price for lubricating fluids.

The critical operating temperature is 40C for a differential.

75w90 is does not provide sufficient protection in most MB applications.

NEVER use a 75w90 in a US Spec differential.

 

85w90 is a synthetic...it is produced by Mobil for Mercedes List is around $30 per liter, if they cut a deal it can be had for around $26.00. This is a high end synthetic not a conventional lube which is why MB is using it on more and more applications becuase of its better protection to the differentials.

In the US we pay about 1/2 the price for lubricating fluids.

The critical operating temperature is 40C for a differential.

75w90 is does not provide sufficient protection in most MB applications.

NEVER use a 75w90 in a US Spec differential.

Ok, people everyone who is been following this thread: Please look all the pictures I am attaching and tell me what is wrong whit them? I want answers based on healthy thinking over those pictures posted; not just chewing same words repeatedly, because you are afraid that thinking can gets you a headache.
I do not thing that 85W90 is synthetic (check this web site Mobilube LS 85W-90), it says that: "Mobil LS 85W-90 is an extra high performance, automotive gear lubricant formulated from select base oils and an advanced additive system specifically for limited-slip differentials". It is been around for long time to be synthetic, and it is been discontinued since 75W90 Delvac Synthetic was developed. And trust me I know about oil and gas and diesel prices in EU, that is why I choose to buy W211 CDI, because I can go back if gets to S***** here. I never ask about it because my car according to first picture is calling for 75W85, am I right, and probably this is true for other member's car and especially for you drivbywire. One of your vehicles is same car like mine; correct me if I am wrong. O and by the way, our differentials are Ø210E. I do not argue about 4matic cars or SUVs may be the rear differential needs same oil, or maybe not, I can check if someone needs info. Second and third picture are info about FUCHS synthetic oil called Titan and made for MB, which I want you people to compare to forth picture representing Mobil1 Gear Oil. Now I want to know which oil has higher viscosity at 40°C, FUCHS or MOBIL1.
What the first picture said, according to drivbywire, is that MB fill up our rear differentials with oil that will fail and will cost 3000 to 3500$ in warranty repair for thousands if not hundreds of thousands cars, correct? Why I should not use 75W90 synthetic oil on car prefilled with 75W85? Kajtek1 and paulv are right: MB drop viscosity of the gear oil when they start using FUCHS synthetic, but they gain better protection compare to conventional 85W90 - THANK YOU Kajtek1 THANK YOU paulv. Now at last I want to know which car differential has working temperature of 40°C, I may spend some money to get one of those for my E.

 

Your information was current back in 2002...it has since been revised (2/2007)!

Go ahead and run a differential fluid that is 30% thinner than the 85w90 which MB now calls for in 2006-2010+.

Viscosity is the key factor, the 75w90 and 75w85 is simply to thin for the differentials. The 75w90 is only called for in the G and R class differentials WITHOUT limited slip, if you have limited slip we go right back to viscosity ie 75w140!

MB has revised that recomendation to only include 85w90 as the primary viscosity range and no longer supports the thinner fluids.

The higher the 40C cSt the better the fluids performance in typical operating temperature ranges.

To quote the STLE mantra "Viscosity, Viscosity, Viscosity!"

Given that all my Mercedes are Diesel, the increased torque going thru the gear boxes is quite a bit higher than that in a gasser. I need a higher viscosity fluid to protect the gear sets and bearings (just as Mercedes recommends).

All the BS aside, I replace the differential fluid with every transmission fluid flush ever 30,000 miles.

Below are all the current supporting documents.

 

According to the 2010 MB Fluid application manual, which is actually from 06/05/2008 according to StarTekInfo web page (see picture below), saying 2003-2010 on the bottom not old info, attached by you drivbywire, you ML and GL with or w/o differential locks call for MB Gear Oil Part No. A001 989 33 03 10 - which is 75W85 check posted information by Noodles and also picture posted by me from Star Service, but you probably read the first page only never going further in that manual like everything else we been discussing here. Be very careful, you do not have enough protection there at low temperature with 85W90. You learn one thing and that is it 85W90, even you cannot change your mind when reading something different. In addition, no, my information is probably more recent than yours is, because the picture from Star Service DVD says ®2007 Mercedes-Benz, LLC on the bottom, but I left it out when resized it (can be PM'd upon request). In addition, why you keep changing your opinion: first, you say that 85W90 has cSt of 153, now you are presenting Mobilube HD-A which is also conventional with cSt 184, I think that you did not read the top of the page, where it says that both oils are been formulated from base oils instead of synthetic basestocks. Why do you thing that MB says that the new oil 75W85 can be used on older cars manifactured before 2001 "without reservations". My guess is that they found that it provides sufficient protection when replace 85W90 or 75W90.
All the B*** S**** aside read everything when is presented to you in easy to digest form, do not hold, on things you know, you may learn something, no one knows everything.
THE TRUTH IS BORN IN DISCUSSIONS, but constructive discussions.
I am suggesting that you go back and READ, READ AND READ MANY MORE TIMES this thread from page one, and take your time to check all pictures and links. Also read the information, which you have, completely, DO NOT CONFRONT YOURSELF.
So far, you are not being able to prove why synthetic oil should not be better than conventional even if you use MB synthetic oil recommended by them with lower viscosity than Mobil1 or Valvoline.

 

So what does a 1997 Supra have to do with a Mercedes Benz topic and 75w90?

The fact remains that only the viscosity range of 85w90 is approved unless otherwise stated for your model.

The MB235.7 85w90 is a synthetic oil
MB Hypoid Gear Oil (85W-90)
MB Part No. A001 989 17 03 10

If you want to trash your differential go for it.

I am simply recomending what Mercedes recomends ie 85w90 and if you had any clue as to why, it would be obvious that a 75w90 is too thin for these applications.

Would you run a 0w20 in your Mercedes engine, thats the difference in viscosity we are talking here when comparing a 75w90 to an MB235.7 85w90.

 

So what does a 1997 Supra have to do with a Mercedes Benz topic and 75w90?

The fact remains that only the viscosity range of 85w90 is approved unless otherwise stated for your model.

Just an example that your differential stil will be protected if you use 75W90 synthetic or conventional, or 75W85 instead of 85W90. I think that you are trying to trash yours if you been putting 85W90 instead of 75W85. READ, READ AND READ EVERYTHIN, do not hold on yours. Now yor are saying "unless otherwise stated for you model".
AND NO IS NOT SYNTHETIC.

 

It depends on the model, some require a thicker fluid ie 75w140 so yes "Unless otherwise stated" because the higher performance models need a thicker fluid.

The issue again is the 85w vs the 75w and that the 75w has 1/3 to 1/2 the viscosity at 40C when comparing to the 85w under the MB235.7 fluids.

The fact is the Manual says that you are wrong, so if you choose to use the incorrect fluid thats your choice.

 

So you are saying that Star Service Manual which covers all USA W211 models from 2003-2008 it is wrong about 75W85 oil in our differentials, that is been fill up in the factory. In addition, the oil manual you are using, mentioning same oil for your ML and GL with or without differential lock, or for G-WAGEN with differential locks is wrong.
This oil is much thinner than Mobil75W90 and is not damaging the rear end, it makes me wonder how the Mobil will not being able to provide protection.
Drivbywire, please take your time and check the pictures I am attaching and explain to me how FUCHS Titan Synthetic Gear Oil 75W85 is better than Mobil1 Synthetic Gear Oil 75W90.

 

OK, here it is. Just got my new original manual for my euro W126 380SE. It says 1.3L Hypoid gear oil SEA (sic?) 90, 85W90. So, I figure I should change it, since who knows when it was changed if ever on this thing. My question is: what is the allen wrench size(s) for the drain and fill plugs so I can procure them?

 

w211 uses 14mm.
SAE 90 can be any oil - 75W90 or 85W90 or only 90. With your location will be better if you go with 75W90, to cover low temperatures.
Here is a link to all MB fluid sheets. MB Hypoid Gear Oil (85W90), MB Part No A001 989 17 03 cannot be found on any of them. The fluid manual posted be drivbywire, dating back to 06/05/2008 says that this oil meets sheet 235.7 specifications, but it is not on that sheet either.

MB 235.7 - Universal hypoid gear oils (Specification 235.7) - Mercedes-Benz Specifications for Operating Fluids

 

Not sure it is the same on a W126.