[Forrester]

I am 110% certain they did not change the oil in the centre section of @Forrester diff.

I was referring to the diff oil change in general. I don’t know the specifics of the middle section. I’m sure @veeeight is right about the middle section.

 

[Akinen]

No no no! Stop! No more muddying!!!!

M-B Germany does not think 235.15 is the correct oil for A45s!!!!


The following Mercedes website is what M-B Germany thinks should go into the rear diff twin clutch coupling…..

See

Mercedes-Benz Operating Fluids

Publication platform for approved operating fluids from Mercedes-Benz

operatingfluids.mercedes-benz.com

@Theo you can show that website ^ to your dealer.

Scroll down till you find:

“Axle gear oils, sheet 235.64 for TWIN rear axle differential rear axle for coupling, model 177 and 118 with engine 139”

235.64
235.64
235.64
235.64
235.64
235.64


And as the Dragon’s say… “I’m out” 😂 😂


*In true Mercedes style, that sheet has an error as it talks about a 9-F DCT for the W177 model Unless @steve_3939 - has the A45s FL got a 9 speed gearbox?

Sorry for mudding again lol but any idea to what is this table refering to with the oil quality 235.15?

EDIT: OK I think it's for A35 models, sorry, this post can be deleted!

 

[Theo]

What if we use the 235.15 for the center section, if we can't find the aftermarket 235.63? The difference is minimal, 75W-85 vs 75W-80 and while it would be smart to get it spot on for the clutch housings, perhaps a slightly thicker oil such as the 235.15 for the center gear set might work just as well. So 235.64 for the two clutches and 235.15 for gear set?

I'm asking because so far I haven't found the 235.63 (see post #208 first two paragraphs) and I have already purchased the 235.15. Have already ordered the 235.64 from dealership.

 

[veeeight]

@veeeight, I have access to two instances of WIS, mid-2021 and late-2022 and neither lists a procedure for changing the clutch oil, but both reference it being required on the maintenance schedules. I have checked both the c118 and w177 sections without luck. If you're able, could you post a screen-shot or excerpt covering the procedure?

No More, I'm out.
@Theo - use a GL5 Hypoid Oil for the centre section as previously linked.

 

[fatty45]

@veeeight - you are a legend, sir! As an avid DIY'er who does not take his vehicle to a shop unless absolutely necessary, I very much appreciate this. And as I suspected, the fill and drain plugs are not reusable, and the clutch oil is electronically monitored and requires a reset when the oil is changed. Thanks again!!!

 

[Forrester]

@veeeight - you are a legend, sir! As an avid DIY'er who does not take his vehicle to a shop unless absolutely necessary, I very much appreciate this. And as I suspected, the fill and drain plugs are not reusable, and the clutch oil is electronically monitored and requires a reset when the oil is changed. Thanks again!!!

Steady with the complements. Getting ones head through the door come to mind. 🤣 Did you have any thoughts on the A35 diff. You briefly touched on it at one point.

 

[fatty45]

Almost DIY time!

 

[veeeight]

"transfer case" or "haldex" or however the unit which transfers the power between the front and rear is called (or is this the what is meant above with the lubed for life "gear set"?)

W177 A45s works differently from the single Haldex/Borg Warner type electronic multi plate clutch in the sense that the single clutch pack connecting front and rear does not exist - instead 2 multi plate clutch packs are installed, one on each half shaft exiting the rear diff, to control each side locking or slipping independently. This is how you can engage one side more than the other giving drift mode.

So the centre section rear diff is conventional hypoid diff gears (“lubed for life”) and the 2 side clutch packs require oil changes with Shell TF 870 B.

 

[Forrester]

@fatty45 just to let you know the A35 element of the thread was moved to (26) A35 AMG Rear differential issue? | Mercedes A-Class Forum (aclassclub.co.uk) If you would like to comment there.

 

[Theo]

@veeeight

So I assume our front open diff doesn't require maintenance?

Also, I don't think I can find one of the 235.63 oils you guys have been talking about. That's why I was wondering if I could use the .15 instead, which is like only 5 grade thicker, you could say practically identical, and only for the middle, less critical section. The way I see it, it's either that or sticking with MB's "lubed for life" for this part. What would you choose if these were your only two choices, with respect to your diff longevity in the long run?

 

[Forrester]

@veeeight

So I assume our front open diff doesn't require maintenance?

Also, I don't think I can find one of the 235.63 oils you guys have been talking about. That's why I was wondering if I could use the .15 instead, which is like only 5 grade thicker, you could say practically identical, and only for the middle, less critical section. The way I see it, it's either that or sticking with MB's "lubed for life" for this part. What would you choose if these were your only two choices, with respect to your diff longevity in the long run?

Given the age and mileage of your car I would accept the lubed for life.

 

[veeeight]

@Theo without checking, I’m pretty sure the front diff is part of the gearbox lube. So no separate maintenance.

Re centre section, personally I would go with a Hypoid GL-5 oil, with viscosity as close to the OE spec. I personally don’t like the idea of the .15 oil, in a set of Hypoid gears. Hypoid gears require Extreme Pressure oils.

 

[Theo]

Given the age and mileage of your car I would accept the lubed for life.

I think "lubed for life" for the center section, does not mean that the oil will actually last indefinitely. If you're going to keep your car for say 20 years with 200k miles on the clock, which is reasonable daily drive mileage, I don't think you're gonna get away with not changing the oil. You're certainly taking a significant risk. But for the majority of A45s owners, that will probably keep it 10 years max with 100k miles on the clock, even with occasional hard driving, it should last just fine. That's what I think "lubed for life" really means. That being said, if you do have access to the right oil, there is no doubt that changing it is the proper way, even if MB says you don't need to. But if you don't, then I really think you'll be better off just leaving it alone. If we're not talking anything extreme such as 20 years and 200k miles, it's far better than using the wrong oil.

@Theo without checking, I’m pretty sure the front diff is part of the gearbox lube. So no separate maintenance.

Re centre section, personally I would go with a Hypoid GL-5 oil, with viscosity as close to the OE spec. I personally don’t like the idea of the .15 oil, in a set of Hypoid gears. Hypoid gears require Extreme Pressure oils.

Could you please take a look at the following GL-5 oils?

MOTUL MOTYLGEAR 75W-80 - Motul

MOTUL MOTYLGEAR 75W-80 Specially recommended for gearboxes hard to shift and Peugeot, Citroën, Renault… gearboxes.All mechanical transmiss

www.motul.com

Hypoid Gear Oil (GL5) SAE 80W

Mineral-based hypoid gear oil. For vehicles with proven transmission technology. Guarantees maximum safety reserves under critical operating conditions. Provides a stable lubricating film and minimizes wear.

www.liqui-moly.com

Hypoid Gear Oil (GL5) SAE 80W-90

Mineral-based hypoid gear oil. For vehicles with proven transmission technology. Ensures assemblies function perfectly, even under extreme operating conditions and when exposed to large temperature fluctuations. Ensures a stable lubricating film. Offers high lubrication reliability and optimal...

www.liqui-moly.com

Would any of these work fine for the center section?

The first one says it's both GL-4 and GL-5 but no hypoid that I can see.

About the other two, the one says 80W and the other 80W-90. What's the difference? Why no hot number on the 80W? Unless that 80 covers both cold start and operating temp, such as an 80W-80.

I've used Motul before but it was a racing brake fluid, very good quality, but I don't know about their oils. As for Liqui Moly, heard good things but never used any of their products.

 

[Forrester]

I think "lubed for life" for the center section, does not mean that the oil will actually last indefinitely. If you're going to keep your car for say 20 years with 200k miles on the clock, which is reasonable daily drive mileage, I don't think you're gonna get away with not changing the oil.

I agree. But I think at this point in time you should be okay.

 

[Akinen]

@Theo without checking, I’m pretty sure the front diff is part of the gearbox lube. So no separate maintenance.

Re centre section, personally I would go with a Hypoid GL-5 oil, with viscosity as close to the OE spec. I personally don’t like the idea of the .15 oil, in a set of Hypoid gears. Hypoid gears require Extreme Pressure oils.

Not sure if I read this table correct but it seems our front diff should take 235.74 or 235.0 oil?

And the DCT needs 236.22 ?

 

[Akinen]

W177 A45s works differently from the single Haldex/Borg Warner type electronic multi plate clutch in the sense that the single clutch pack connecting front and rear does not exist - instead 2 multi plate clutch packs are installed, one on each half shaft exiting the rear diff, to control each side locking or slipping independently. This is how you can engage one side more than the other giving drift mode.

So the centre section rear diff is conventional hypoid diff gears (“lubed for life”) and the 2 side clutch packs require oil changes with Shell TF 870 B.

Does this mean that the clutch packs on each rear wheel not only control the torque "left to rear" but also "front to back" 🤯 ?

 

[Turbo Ed]

Does this mean that the clutch packs on each rear wheel not only control the torque "left to rear" but also "front to back" 🤯 ?

@Akinen
I was waiting for @veeeight to point out that he has explained this situation on multiple occasions, in multiple posts, going back at least three years.
However, I would suggest given the delay in answering you, he is probably well and truly over it !!

You "could" argue that the side clutch packs "sort of" control torque front to back, in very unusual scenarios.
Say, front tires on ice, no ice under rear tires.

However, under normal conditions the toque split, front gearbox out to rear differential in, is simply 50 / 50, as it is just a PTO at the gearbox outputting to the driveshaft.
What matters though, then, is what the clutches on the output of the rear differential, DO with the 50% maximum gearbox output torque being provided to them.
THAT certainly varies with conditions, and I suppose one could, somewhat obtusely argue that their operation is "controlling the torque front to back".
Bit of a stretch, though!!
(As @veeeight has frequently and accurately pointed out)

 

[Theo]

Just picked up the final parts for the whole service, the 235.64 oil and the gasket seal for the gearbox.

So guess what arrived today, 1 liter of Shell TF 0870 B. The one we've been talking about, except I got it from the dealership, so apparently that's the one MB provides as 235.64. Wasn't expecting that. Also got the rubber gasket seal for the gearbox, so I'm finally ready for the complete, as per MB schedule, diff and gearbox service, but still need to decide what to do with the 235.63, which, frankly, I might just skip for now, as I'm not sure I've found the right oils.

And I picked up 6 liters of AMG 0W-40 but I had to find another source as it has been discontinued by the local MB distributor. Dealership now only provides the Petronas 5W-40, which I wouldn't hesitate using, but prefer the AMG which I've been running since the first oil change. Got the oil filter too, just because they said they only had 5 pcs left.

 

[Turbo Ed]

Just picked up the final parts for the whole service, the 235.64 oil and the gasket seal for the gearbox.

So guess what arrived today, 1 liter of Shell TF 0870 B. The one we've been talking about, except I got it from the dealership, so apparently that's the one MB provides as 235.64. Wasn't expecting that. Also got the rubber gasket seal for the gearbox, so I'm finally ready for the complete, as per MB schedule, diff and gearbox service, but still need to decide what to do with the 235.63, which, frankly, I might just skip for now, as I'm not sure I've found the right oils.

And I picked up 6 liters of AMG 0W-40 but I had to find another source as it has been discontinued by the local MB distributor. Dealership now only provides the Petronas 5W-40, which I wouldn't hesitate using, but prefer the AMG which I've been running since the first oil change. Got the oil filter too, just because they said they only had 5 pcs left.

@Theo,

The Shell TF0870B is what is supplied, in Shell packaging, by MB Australia, also, so I am guessing it is a worldwide scenario.
It simply shows the low volume nature of our vehicles, in that it is not worth MB / AMG's while to even bother with re packaging, as they would do for the more commonly used lubricants.

 

[veeeight]

Speaking of rear diff oil changes - @TTG had to have a premature rear diff oil change to cure a rear diff knocking noise problem:

Recall at B service time

Our car was in for some warranty work this week which they ended up not doing because one of the parts was wrong but they also said they couldn’t continue till recall was complete, I’ve done a vin search and nothing is showing as to what issue is with cooling hoses, anyone with any inside info...

www.aclassclub.co.uk