[Theo]

Thanks for the heads up.

Seems like the 235.63 is now widely available. That was fast, only took them four years after the first M139's hit the market.
Here's mine, luckily only took a couple of days to arrive as I ordered it last week. It's same batch as yours too.

The BMW oil has served its purpose, being the closest available alternative. Ran it for 2-2.5k miles, but it's time that the diff gets the oil that was meant for it. Booking an appointment for next week, together with an engine oil change, my usual AMG 0W-40, which I've been purchasing online since last Spring (6-month oil changes), as it's no longer available at the dealer.

 

[Theo]

Maybe. But there seems to be a theme running through this. It's that third service which seems to be problematic to more than one of us.

I mean, I thought the database with the oils and procedure would've been available everywhere by now. Can't screw this up. I stayed and watched the entire process it's really not less straightforward than a spark plug replacement. And if you use different oils from those listed, you're dumb. I would understand the difficulties in case where the third service was done incorrectly the first time, say back in 2023 when things were a little blurry, diff started acting up because of it and now they had to figure out the problem, is it software, is it hardware, is it oils? That's a little different. But screw this up now, in 2025?

 

[Theo]

It takes us back on topic for this thread. I would be interested in what the garage says about your rear diff oil. I would imagine it's quite black compared to many other A45s they change the oil for. I'm sure your selection does cause much great rear torque transfer. This is probably where we need @Turbo Ed and @Theo input, but I thought our cars were 100% fwd unless otherwise needed.

Well mine and @fatty45's both came out dark, but my center section was nice and amber, you could say like new.

As for the drivetrain I thought the same and the reason I can easily powerslide as I often do in 3rd gear when exiting a turn is that I give it enough gas to cause the front wheels to lose traction, and the rear outer wheel steps in with a certain % before the car starts to understeer. Normally that will straighten you up, but if you go a little harder, that wheel can get up to 50% of power and cause you to oversteer. Then you counter steer and what that does is it shifts the power sent to the rear over to the other wheel which is now the outer wheel and you exit the turn nice and smooth. In such situations, the front wheels do very little to put the power down so the car is essentially RWD, and the reason the previous RS3 was known to understeer is that the power was sent to both the rear wheels, which kept pushing the car forward instead of trying to put it back on track (or oversteer if you went a little harder). They've allegedly fixed that with their new torque vectoring system which is similar to ours, but I've been reading that ours is still a bit more rear biased. Not sure why that would be, if it's true, but my guess is it's about the timing, i.e. ETA before the rear diff does its thing, and the algorithm which dictates the % of power that's sent to the rear based on the % of traction loss up front.

That's how it works. You drive aggressively around corners or doing launches and low rolls more often than not, you wear your tires faster because you're sending more power to the rear more often, not sure about the diff I dunno the kind of abuse it can take but I bet it'll take several sets of tires before that itself starts to go, otherwise it's a joke. In a stock car.

 

[Theo]

And once more I'd like to thank you for finding the BMW oil alternative. Your contribution was valuable for those who decide to change that out too. Big thumbs up man!

 

[Theo]

Everything we are seeing, from Spark Plugs to Lubricants, tells me we are dealing with a VERY low volume production vehicle, worldwide.
When I am at the engine plant in early September, I shall ask what the daily engine production numbers are.

Maybe the M139 division is down to one man, so it would be "one man all engines". Two engines a day.

 

[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.

 

[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.

 

[Theo]

Yes they did. But I will never know if they used the one that we have all identifies as the correct one.

Wait, how did they perform any work on the center section, for which there is no official procedure?

 

[Theo]

Interesting in that they describe this oil as for use in BOTH transmissions AND hypoid rear axle assemblies.

I've noticed that too. Same with the Titan Sintofluid 75W-80 GL-5. Apparently the two applications are very similar.

@Theo, the fill amounts are found in WIS and are as follows:
Right Clutch Housing Capacity: 0.35 liters
Left Clutch Housing Capacity: 0.37 liters
Center Gear Set Housing Capacity: 0.48 liters

So 1 liter of each oil type and you should be good to go for a full rear axle service.

Excellent, thanks.

The other thing is letting the dealership work on something they aren't trained for and without having a procedure to follow. I'm referring to the gear set housing 235.63 oil. I'm a little concerned... I mean what if I skip that? You know this isn't the first "lubed for life" case I've seen, there are dual clutch gearboxes just like that and they don't fail.

 

[Theo]

No aftermarket version of 235.64 in this country, to the best of my knowledge, which is precisely why my independent keeps buying it from the local MB Dealership.

In all my vehicles, this would be the first time I have had to do this in at least 40 years.

So if I can't find any aftermarket versions, and dealership can't get me the 235.64, I'll dump in the 235.15 which they claim is the correct oil and enjoy my rear differential for as long as it lasts. What else can I use, I can't pee in there can I?

 

[Theo]

I might even be in LA if your engine is late 😁

You mean cruise to LA.

 

[Theo]

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

 

[Theo]

Picked up a few things that arrived recently, don't really know when, I didn't get a call as I explicitly requested. Perhaps they didn't think I needed it, as I ought to have upgraded myself to the 6th sense. So I called them instead.

The little box is listed as the oil cooler filter and the bigger ones as oil filters.
The little o-ring on the left is listed as an o-ring seal (profile) and the bigger ones as o-rings.

And now we come to what really worries me, the diff oil. As you can see they gave me the 235.15 approval which, as I've been reading here, is not the right one for our twin clutch system. I looked in the bag just to make sure, and I immediately asked why it's not the 235.64 which is the right one based on what I've read. They went like "where did you find that info" typical dealership response like I'm some dumbass clueless rich dude owning a six figure car, not supposed to worry about anything going into the engine and other components, and I said "from owners in the UK, that's the one they use". Guy said, "so that's what they use in the UK, it's country-specific". I said, so how come we use the same engine oil 0W-20, no matter if I have personally decided to stick to the AMG 0W-40 as I would use the 20 to boil my spaghetti in our blazing hot summer, the 0W-20 is still the recommended one, which is the same in both countries. So same engine oil but we use different diff oil? doesn't make much sense. He said he would run another check based on my VIN, but I don't think that is going to change anything as all orders are based on VIN in the first place. Perfect...

I have sent MB an inquiry, asking which is the right diff oil approval for my car and in my region.
Waiting for their response.

 

[Theo]

Ok so I picked up 6lt of ATF - M-B 236.22 - A000989610409 and I was told it takes up 5.something.

Now on to the diff left and right section oil, DCT filter etc, and plugs... and let the wait begin (hope not).

 

[Theo]

This following example is the dealership not filling the M139 engine with the correct spec oil at service….. Mind Boggling.

https://www.aclassclub.co.uk/threads/wrong-oil-used-at-service-2022-a45s-m139.25313/

And somebody hired these people...

Reason why I never let the car out of my sight when it goes in, since the first car I've owned. It's two days of the year, it's worth the wait. Only with the A45s it hasn't been easier as I can take a walk or sit comfortably in the waiting room and the car will let me know when it goes in. One other thing I do is bring all the service parts and consumables myself, which I have previously bought from either the dealer or somewhere else, and I stay and watch to make sure every last part is unpacked and used/installed. That way I have complete control over the entire service. I'm committed to it. My car is my property, I'm not leaving it at the dealer expecting they'll respect and treat it as their own, because they won't, and you know why? Not because they don't want to, but because it's just another car, they can't see it as the result of my effort. The only other people that can see it as such, is your family and dearest friends, not even all your friends. Because it ultimately comes down to respecting you, deeply.

 

[Theo]

Man I didn't even notice that temporary knock. Car left the dealership in the same way it got in, if I hadn't watched every bit of the process I wouldn't have been able to tell they did anything. Can't believe I'm reading all this. Best of luck sorting it out, I would request another diff oil change like you said, but wouldn't let the car out of my sight and check the bottle before it went in.

 

[Theo]

Don't remind me, I got blood pressure through the roof that day. Then I decided the only way for them to see it, was if I got them the printed documents straight out of MB. They still looked at me like I had come from the future, but quickly realized I had come in peace.

Jokes aside, I think the guys over at the spare parts were the problem, not the garage. The garage did everything by the book, checked WIS and proceeded as instructed. They also gave me a printout of the whole thing, which did mention the right oils.

I don't mean to justify their ignorance, but it was 2023 with all that chaos worldwide, and on top of that mine was the first M139 in the country back in 3/2020 so obviously the first at the 3 year service. I'm more surprised there are dealers with the same ignorance two years later. Car is being phased out and they'll keep screwing up the diff service.

 

[Theo]

Boggles my mind one could screw up something as straightforward as this. The only thing I could understand not getting changed is the center section gear oil as there were no instructions at the time and dealers would have to take full responsibility for potential damage, even if that too was as straightforward as it could get. But that's how it works, it's protocol. I was surprised mine not only didn't hesitate to change it, they recommended it too. I was a little worried about the torque specification as there was no reference of it either and the tech would have to rely on experience, but everything went smooth and two years later it's all good. But mess up the official clutchpacks procedure, that's epic.

 

[Theo]

I got sick after that ^ post, just common cold, then we had very poor weather and didn't want to ruin the beautiful striking matte gray for a meaningless oil change, then my wife got the cold and I was looking after her, then she got covid which I got from her couple days later, spent Christmas drinking herbs and chicken soups and couldn't be at the new years either as I was still positive, albeit perfectly well otherwise, January was mad at work and then I wanted to be with my wife on her 7-day business trip to Vienna, her mother came along with us and she got covid while we were there, was caughing bad for the first couple of days but didn't take long to recover, thank God she got the shot 3 weeks earlier, sooo ended up taking the car in last Thursday.

Exactly 500ml of BMW GL-5 came out, let it bleed out to one drop coming out every 5-6 seconds, exactly 500ml of 235.63 went in. Also 5.8 liters of fresh 0W-40 AMG engine oil and filter went in to complete my unofficial 6-month service and thought it would be a good idea to check the battery while I was there, as it's now almost 4 years old, still ok according to the scan, and next official service coming up early June.

In about a month from now I need to take it in for safety and emissions inspection (the MOT equivalent), probably going to need new tires by next summer and I need to check my brake rotors thickness as I don't think they will last long either. Seriously considering picking up the Paragons for both the fronts and rears, if only for weight saving, considering I don't intend to go far with power upgrades. 11kg of unsprung weight reduction isn't bad at all and should complement my upcoming 470hp and 594nm quite nicely.

 

[Theo]

LOL!!

Again, @Theo, you crack me up!!
Are you coming up to Stuttgart or I need to fill my third spot by inviting @veeeight?

If it's going to be @veeeight I will happily offer my spot, on the condition that @Akinen would film your non-ending debates throughout the whole trip. Should provide footage for the next six months.

Jokes aside, chances are I won't be able to make it. My wife works for the Greek Atomic Energy Commission and September will be a crazy month as they are hosting a European event. There will be so much going on to leave her behind, even if I could manage things at work myself. I'm sorry mate.