[veeeight]

What model rear diff oil needs to be replaced ？75W-85？75W-90or75W-140？

For the replacement interval - see post #49 above.

For the actual spec of the rear diff oil - best to check with the dealer as there may be more than 1 type needed.

Gear set - M-B 235.63 75W-80
Coupling - M-B 235.64 74W-70

See
Link

 

[veeeight]

still？Just use one standard ？

No, because wet clutch packs has different requirements to final drive gears for slip.

 

[veeeight]

Someone changed ，He uses it directly ，Already driven 17000 km No problem 。So I'm thinking ，Is it possible to calibrate ？
He used 75W-90.

You can do it at your own risk. But may not work successfully in all climates, temperatures, conditions and torque.

 

[veeeight]

Yep，Because the original factory is 75W-85

Gear set - M-B 235.63 75W-80
Coupling - M-B 235.64 74W-70

 

[veeeight]

M-B 235.15 is for W177 4MATIC rear axle, eg A250 4MATIC.

A45s with TWINster type e-clutch locking clutch packs is different. (4MATIC+, although that’s just a marketing term). M-B spec sheet says you need 235.63 and 235.64 for that.

In terms of just viscosity - they are very similar. But twin clutch pack needs specific properties for correct torque transfer and slippage, so I’m not sure 235.15 will deliver that under all conditions

 

[veeeight]

According to my list:

Rear Diff:
Gear set - M-B 235.63 - not in service schedule, "lubed for life" 😂
Coupling - M-B 235.64 - A0009894406
No diff filter. Left and Right coupling separate fills.



Gearbox (I'm not 100% sure of the parts below, so check with your dealer):
Filter - A2463772300
O Ring - A0229978045
ATF - M-B 236.22 - A0009896104

 

[veeeight]

Number 1 reason for changing the A45s rear coupling sections (Left & Right) more often, as opposed to less often:

The A45s configuration and calibration is to give “more” rear drive feeling, say compared to a Golf 8R. So the rear coupling clutches (Left & Right) are experiencing more slip engagement more of the time. Slipping clutches in oil leads the oil to deteriorate quicker than non slipping clutches

The M-B spec oil for the rear couplings (Left & Right) is M-B 235.64 - A0009894406. 0.4 litres per side. Shell Equivalent TF0870 B. The “B” is different to the G8R non-B oil suffix? Does this make a huge difference? Don’t know.🤷‍♂️ But I would stick to the M-B part number above.

 

[veeeight]

Was our friend in the ME correct regarding Magna being the Tier One on the VAG differential assemblies?

Yes Magna is supplier for G8R and RS3 rears.

With respect to A45s it’s more murky! - I was always told that that AMG did the development with Steyr - but of course Magna bought Steyr. But more likely AMG worked with Steyr OE in-house engineers, so the calibration IP of Audi and AMG would not be available to each other.

But neither AMG nor Magna have ever declared in public that Magna supply the A45s rear unit, or that it is the same unit as in G8R/RS3, only a couple of motoring journalists have put 2&2 together and maybe come up with 5.

So could they share a casing? Possibly. Internals? Possibly very similar. Or they could be different units!

M-B has no service schedule for the actual centre gear set though. ie no replacing of the oil, which they say “isn’t available” (M-B 235.63). VW/Audi has. 🤷‍♂️

 

[veeeight]

@veeeight, are you able to identify which of the Magna Europe plants builds the rear axle assembly in the VAG product?

No, I don't know. If I were to guess, Graz. But that's a guess. Low-Res drawings of the rear drives of the G8R and A45s show the mounts and casings look different. So maybe just similar internals? After all, there only a limited number of ways you can get a twin clutch and hypoid gear set to look

and WIS lists no procedure for changing the rear axle oil – not for the center section

M-B do not have a schedule or procedure for changing the centre hypoid gear set oil. "Lubed for Life"........ and do not list any products for 235.63 oil. I dare say that regular changes of a good quality 75W80 Hypoid oil will be suitable, if you are so inclined

 

[veeeight]

75w80 Synthetic Gear / Diff Oil GL-5

Fully Synthetic 75w80 Premium Gear / Differential Oil Fully synthetic gear oil is a high performance product manufactured from a blend of synthetic oils, sheer stable viscosity index improvers and a multipurpose extreme pressure additive system. It offers a high level of performance when...

www.westwayoils.co.uk

 

[veeeight]

I note with interest @veeeight has also recommended a specialty lubrication company, however more conveniently based in the UK.

I usually use Smith and Allan Lubricants, in the UK, but they don’t list that particular GL-5 Hypoid Oil.

 

[veeeight]

My recollection is that GL-5 EP additives withstand higher pressures, so in a closed diff application like a rear axle it probably lasts longer.

But in reality the differences are probably marginal in the A45s application, I mean if you're talking commercial truck rear axles and loads, that's probably more relevant.

 

[veeeight]

Just product differentiation. M-B wanted to keep “Drift Mode” for the A45.

 

[veeeight]

@Theo there are 2 sorts of “rear diff” oil in the A45s.

The centre section gear set - Hypoid Oil - which MB do not list a part number for its replacement as it’s “lubed for life”.

The twin clutch x2 oil - which is 235.64.

 

[veeeight]

The photo shows 235.15 for the diff oil. Which I presume MB in Germany thought was correct.

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?

 

[veeeight]

I’ve just noticed something in that document re the earlier discussion about GL-4 and GL-5 spec oils:

“However, the hypoid gear oils must at least correspond to the US military specification MIL-L-2105 B/C/D and must be classed GL-5 in the quality grade according to API (American Institute of Petroleum).”

 

[veeeight]

@veeeight so the 235.15 that they gave me is for the single clutch differential systems, not suitable for our twin unit.

I have given up trying to second guess why dealers give out the parts/lubes they do! No idea why they thought 235.15 was correct for your car. Unless they have an instruction that says substitution is OK…….


M-B 235.64 is Shell TF 0870 B - which if you look at the description - is approved for Magna Powertrain:

Shell TF 0870 B 209 Liter

<strong>Shell TF 0870 B</strong><br /> Synthetisches Verteilergetriebeöl<br /> <br /> Shell TF-0870-B ist ein Hochleistungs-Getriebeöle für spezielle Verteilergetriebe von Magna Powertrain und Mercedes-Benz Hinterachsgetriebe nach MB 235.64

www.kreissler24.de

 

[veeeight]

Someone replied to a similar thread on another forum that A000-989-36-08-11 satisfies MB235.63 requirement. I asked for more details (source) but have not received a reply yet. Additionally, I searched (from US) for this part number and it shows "Transmission Oil" and costs $73 USD per liter! I have not been able to find any application info. Anyone know anything about this part number?

12 x 1 litre bottles

No further info.

 

[veeeight]

Yup.

Correlates well to what I posted in previous threads/posts.

M-B 235.64 is Shell TF 0870 B


You can have 209 litres of the stuff here

Shell TF 0870 B 209 Liter

<strong>Shell TF 0870 B</strong><br /> Synthetisches Verteilergetriebeöl<br /> <br /> Shell TF-0870-B ist ein Hochleistungs-Getriebeöle für spezielle Verteilergetriebe von Magna Powertrain und Mercedes-Benz Hinterachsgetriebe nach MB 235.64

www.kreissler24.de

 

[veeeight]

Their product is called Titan Sintofluid 75W-80.

@Turbo Ed - I would have thought something from their Sintopoid Hypoid range would be more suitable?