[thebadboy]

Hello, I need to replace the rear differential oil on my M2 C.

I wanted to put "castrol transmax limited slip 70w140 or Motul Gear Compétition 75W 140 "I don't know why but these oils cannot be found in EUROPE at the moment.

Can you tell me if "RAVENOL Transmission oil SLS SAE 75W-140 GL 5 LS" can fit and if it is as good as the other two.


thank you

[M Fifty]

Maybe just buy from BMW?

[thebadboy]

In BELGIUM, BMW likes to scam people on oil (laughs), I asked for the price, it's almost 40€/L.

I'm not stingy but not crazy either. For example, engine oil at BMW 0w30 is 36€/L.

I bought a 20L container of CASTROL 5w30 M for 8.5€/L. If I have no choice, I will take BMW.

[M Fifty]

You can - apparently - buy the oil you're after from Italy on eBay. it will cost significantly more than 40€/L as it isn't engine oil.

But, why do you need to change it? Castrol themselves suggest a 90000 km/ 72 months service interval.

HTH

[chris719]

Originally Posted by thebadboy

Hello, I need to replace the rear differential oil on my M2 C.

I wanted to put "castrol transmax limited slip 70w140 or Motul Gear Compétition 75W 140 "I don't know why but these oils cannot be found in EUROPE at the moment.

Can you tell me if "RAVENOL Transmission oil SLS SAE 75W-140 GL 5 LS" can fit and if it is as good as the other two.


thank you

Use the BMW or Castrol SAF-XJ. Nothing else. These differentials are prone to issues and it's not recommended to use anything but MSP/A or SAF-XJ.

[thebadboy]

Originally Posted by M Fifty

You can - apparently - buy the oil you're after from Italy on eBay. it will cost significantly more than 40€/L as it isn't engine oil.

But, why do you need to change it? Castrol themselves suggest a 90000 km/ 72 months service interval.

HTH

my car is 4 years old and for the price it costs it would be stupid to deprive yourself of it. Maybe by chance, but I have always replaced my oils regularly and I have never had a problem.

[thebadboy]

Originally Posted by chris719

Use the BMW or Castrol SAF-XJ. Nothing else. These differentials are prone to issues and it's not recommended to use anything but MSP/A or SAF-XJ.

on the CASTROL site, I cannot find the information if it is SAF-XJ but for the M2 C castrol recommends TRANSMAX (not SYNTRAX)

[M Fifty]

Originally Posted by thebadboy

on the CASTROL site, I cannot find the information if it is SAF-XJ but for the M2 C castrol recommends TRANSMAX (not SYNTRAX)

SAF XJ has been superseded - twice. So, what you're looking for is the latest iteration.

You're still 2 years inside the recommended service interval, so relax and stick with the recommended (current) product when it's actually due.

Unless you're a Drift racer.

[chris719]

Originally Posted by thebadboy

on the castrol site, i cannot find the information if it is saf-xj but for the m2 c castrol recommends transmax (not syntrax)

bmw pn: 83222357992

I would still just use the BMW MSP/A or whatever is the latest recommendation. I believe it is 83222365988.

[F87source]

Originally Posted by chris719

bmw pn: 83222357992

I would still just use the BMW MSP/A or whatever is the latest recommendation. I believe it is 83222365988.

I always recommend sticking with OEM fluids for the diff because they are so finnicky. So MSP/A if you can get it - I believe Europe still uses MSP/A (I think Canada is switching to SAF-XJ now), or SAF-XJ (remember it has to be exactly SAF - XJ, not SAF - XJ + FM as the FM is additional friciton modifiers and meant for the E9x m3 and will blow your F8x E diff).


The reason why I didn't buy Castrol syntrax limited slip gear oil was because it is also compatible with the E9X m3 which requires more friction modifiers to stay quiet and operate optimally. So if this gear oil works with the E9x m3 will it have too much friction modifiers for the F8x e-diff? I emailed castrol to ask about this and they could not dig up any more technical data or certifications from bmw, so it really didn't give me any extra confidence, so I would just stick with OEM fluids.

[thebadboy]

then CASTOL TRANSMAX may be the right oil, they are stingy with information on the CASTROL site. So don't take any risks and stay on the oem version

[F87source]

Originally Posted by thebadboy

then CASTOL TRANSMAX may be the right oil, they are stingy with information on the CASTROL site. So don't take any risks and stay on the oem version

Transmax is gearbox oil, it is defintely not the right oil. Also ISTA doesn't even specify its compatibility (ISTA does mention syntrax though - but again my communications with castrol were not promising).

In summary yes, don't take any risks with the diff, stick with OEM fluids you get at the dealership. With the transmission and engine oil you can experiment, with the diff don't mess around.

[thebadboy]

TRANSMAX is a limited slip differential oil or else they write lies on their website


https://www.castrol.com/fr_be/belgiu...f%C3%A9rentiel

[chris719]

Originally Posted by thebadboy

TRANSMAX is a limited slip differential oil or else they write lies on their website


https://www.castrol.com/fr_be/belgiu...f%C3%A9rentiel

Why risk it? To save a few euros? If you prefer Castrol just get SAF-XJ without FM.

[thebadboy]

not at all, following our discussions it is certain that I will take the oem oil as we are not on CASTROL oil or another brand.

If I was sure that castrol oil was good I will definitely take it, what pay more for the same thing, but that is not the case so I will take oem

[F87source]

Originally Posted by thebadboy

TRANSMAX is a limited slip differential oil or else they write lies on their website


https://www.castrol.com/fr_be/belgiu...f%C3%A9rentiel

Oh yeah that's a completely different transmax than what I'm seeing on the north American site: https://www.castrol.com/en_ca/canada/home/motor-oil-and-fluids/auto-transmission-fluids.html#tab_transmax-full-synthetic-multi-vehicle


Very interesting find, I think that's European only as I cannot find this in any north American shops. But here are a few concerns:

1) I can't check if it's bmw certified via ista because my ista is a few years out of date, so I can't verify it for you. But Castrol is unlikely to lie so bmw probably did approve it.

2) is it also e9x m3 and f8x compatible? Because that leads me to be worried there is too much FM, and we know the saf - xj + FM blows the f8x diffs, and witbout the extra FM the e9x diffs get loud and clunky. This is the same dibacle I had with syntrax which is listed in ista as compatible. If you can get Castrol to clear things up for you then that'll be more confidence inspiring that my thought experiment.


Again, these diffs are pretty sensitive so imo I'd only go OEM fluids. There's a reason why bmw sells a different fluid for the e9x and f8x diffs, and it's not one size fits all.


Real OEM: https://www.realoem.com/bmw/enUS/part?id=KG93-USA-06-2013-E92N-BMW-M3&mg=33&sg=05&diagId=33_1418&q=83222282583

This is the e9x diffs oil, notice it requires a booster.


This is an ecs tuning link: https://www.ecstuning.com/b-genuine-bmw-parts/motorsport-rear-differential-fluid-saf-xjfm-5-liter/83222282583/

The booster is additional fm.

[F87source]

Originally Posted by thebadboy

not at all, following our discussions it is certain that I will take the oem oil as we are not on CASTROL oil or another brand.

If I was sure that castrol oil was good I will definitely take it, what pay more for the same thing, but that is not the case so I will take oem

I was also going to go aftermarket with syntrax, because generally aftermarket fluids can (but not always) offer better performance when they don't have to cater to OEM stringencies for fuel efficiency (low viscosity oils) or oxidation (you just have to change the fluids sooner).

But in this case I couldn't quell my ocd knowing that bmw sells 2 different oils, and that if you mix it up the f8x diffs (which are know to be finnicky) will fail. So it was just better to stick with OEM imo, especially since these diffs have had their fair share of reliability issues.

[thebadboy]

the limited-slip differentials are so finicky on the f8x. I will contact CASTROL for more information. the technologies are so different between f8x and E9x that only FM does damage

[M Fifty]

Originally Posted by F87source

Oh yeah that's a completely different transmax than what I'm seeing on the north American site: https://www.castrol.com/en_ca/canada...-multi-vehicle


Very interesting find, I think that's European only as I cannot find this in any north American shops. But here are a few concerns:

1) I can't check if it's bmw certified via ista because my ista is a few years out of date, so I can't verify it for you. But Castrol is unlikely to lie so bmw probably did approve it.

2) is it also e9x m3 and f8x compatible? Because that leads me to be worried there is too much FM, and we know the saf - xj + FM blows the f8x diffs, and witbout the extra FM the e9x diffs get loud and clunky. This is the same dibacle I had with syntrax which is listed in ista as compatible. If you can get Castrol to clear things up for you then that'll be more confidence inspiring that my thought experiment.


Again, these diffs are pretty sensitive so imo I'd only go OEM fluids. There's a reason why bmw sells a different fluid for the e9x and f8x diffs, and it's not one size fits all.


Real OEM: https://www.realoem.com/bmw/enUS/par...&q=83222282583

This is the e9x diffs oil, notice it requires a booster.


This is an ecs tuning link: https://www.ecstuning.com/b-genuine-...r/83222282583/

The booster is additional fm.

Out of curiosity, what happens when you use the "FIND THE RIGHT OIL" function on the Castrol Canada(English) website and look for the M2?

[F87source]

Originally Posted by thebadboy

the limited-slip differentials are so finicky on the f8x. I will contact CASTROL for more information. the technologies are so different between f8x and E9x that only FM does damage

Yeah keep us posted, I contacted them 2 years ago and went up the customer support chain and at the end they couldn't give me any info.


But don't forget, all lsd's have FM (friction modifiers) it's the amount that makes the difference. The e9x diffs use diff oil with FM booster, and that extra booster damages the f8x e-diff. So it's not the FM that causes the damage, it's how much.

[F87source]

Originally Posted by M Fifty

Out of curiosity, what happens when you use the "FIND THE RIGHT OIL" function on the Castrol Canada(English) website and look for the M2?

For me it says: "SORRY!
Unfortunately we cannot determine a suitable product for your vehicle.
This may be because we do not have a product that matches your vehicle�s specifications, or more information regarding your vehicle is needed.
Please contact your local Castrol retailer for a specific product recommendation."


Regardless I don't use a manufacturers website to look for product compatibility, that's how you end up using some product that "meets the oem's specifications" but was never actually approved. I go through the OEM and find actual approved fluids.

[thebadboy]

on REALOEM here is the recommended oil number 83222365988