[F87source]

Originally Posted by Westersund

You can re-use the diff plugs as well as long as the o-ring sits proud, if it doesn't you can always change the o-ring only.

+1

But it is hard to find O-rings that are gear oil compatible and won't swell, I know Turner motorsports has some for their own magnetic drain plugs that likely will fit the stock plugs, but shipping might not make it worth it.

Originally Posted by doughboy

I'm sure you can, but as it's only £3 for the OE plug and o-ring I'd rather just get new ones.

Easier than hunting for an o-ring on the day.

+1

me too.

[Track/S]

Originally Posted by F87source

But it is hard to find O-rings that are gear oil compatible and won't swell, I know Turner motorsports has some for their own magnetic drain plugs that likely will fit the stock plugs, but shipping might not make it worth it.

ista/google doesn't say which O-ring we should use?
They are called VITON, and they can be easily found....

No need to change diff drain plugs, as much as ista says so... Diff plugs can be used without O-ring.

[E90convert]

F87source did share the ISTA screenshot and it’s clear that BMW wants you to change the plug/o-ring assembly. BMW probably purchases the plug and O-ring already as an assembly from the supplier. This is common practice in automotive manufacturing. This does not mean all oil sealing O-rings need to be replaced when removed. In the M diff use case, the blue elastomer (likely Viton) O-ring material, probably degrades faster due to the friction modifier additives in the oil that is required by the limited slip diff. If you don’t replace it, this doesn’t mean you’re immediately going to have a leak. Some friction modifier’s can be especially harsh on rubber seals, and RTV gaskets. I didn’t replace mine plugs when I changed my diff oil. Best practice is to replace them, but if you choose not to, Just keep an eye on it and see if there’s any weepage indicating the O-ring, has degraded to the point of letting oil passed it.

[F87source]

Originally Posted by Track/S

ista/google doesn't say which O-ring we should use?
They are called VITON, and they can be easily found....

Yes I know they're very likely viton, that's the exact one turner sells.

But the exact size isn't always available locally on shelves, so it's not worth it paying $10+ for shipping when you could buy new drain bolts for the same price. So what's available locally will likely not be gear oil compatible - hence it's hard to find an O-ring that fits and will be gear oil compatible.

Originally Posted by Track/S

No need to change drain plugs, as much as ista says so... Diff plugs can be used without O-ring.

Yet another reason for people to avoid your shop. You literally sound like the type of shop that doesn't care about anything, pretty much screw what bmw says I know more - "tight is tight", "reuses crush washers and tty bolts".


Also where's your engineering degree? Because you seem to know more than the bmw AG engineers. You'd also know threads alone don't seal perfectly all the time, especially when the mating surface was designed for a oring to seal it.

[Track/S]

Originally Posted by istaMAN

"reuses crush washers and tty bolts".

Who hell is talking about crush washer's?

First you don't know what type of o-ring supports diff oil and now you know because you read it on google, phatetic....


You need 3 lives to get to change the diff oil as many times as I do, so I can teach you and 50 more like you.

Originally Posted by E90convert

F87source did share the ISTA screenshot and it’s clear that BMW wants you to change the plug/o-ring assembly. BMW probably purchases the plug and O-ring already as an assembly from the supplier. This is common practice in automotive manufacturing. This does not mean all oil sealing O-rings need to be replaced when removed. In the M diff use case, the blue elastomer (likely Viton) O-ring material, probably degrades faster due to the friction modifier additives in the oil that is required by the limited slip diff. If you don’t replace it, this doesn’t mean you’re immediately going to have a leak. Some friction modifier’s can be especially harsh on rubber seals, and RTV gaskets. I didn’t replace mine plugs when I changed my diff oil. Best practice is to replace them, but if you choose not to, Just keep an eye on it and see if there’s any weepage indicating the O-ring, has degraded to the point of letting oil passed it.

Bmw does very stupid things, such as using an o-ring in the diff and not using it in the gearbox, or mounting crankhub without keying...
The diff plug o-ring is completely unnecessary.

[F87source]

Originally Posted by Track/S

Who hell is talking about crush washer's?

First you don't know what type of o-ring supports diff oil and now you know because you read it on google, phatetic....


You need 3 lives to get to change the diff oil as many times as I do, so I can teach you and 50 more like you.

I'm saying you're exactly the type of guy to reuse crush washers during an oil change.


Right, it definitely wasn't when I was examing turner's magnetic drain bolts, or when I use viton hoses in the laboratory - because viton is great when you have to deal with acids.


And yet with "3 lives worth of experience" you still can't follow bmw's guidelines lol. Experience means nothing when you're unable to learn new things and accept things other than your own internal narrative. You've proven that to be true when you couldn't even accept peer reviewed research on carbon build up.

[Track/S]

Originally Posted by F87source

reviewed research on carbon build up.

You're still crying? Accept it and keep learning!
Although you look like a donkey, even explaining yourself you still don't understand.

[F87source]

Originally Posted by Track/S

You're still crying? Accept it and keep learning!
Although you look like a donkey, even explaining yourself you still don't understand.

Lol I assure you I'm not crying, I'm laughing everytime you expose yourself as incomptent, and narcissistic enough to think you tinkering on a microscopic percentage of the total cars in the entire world can prove causation from correlation better and more accurately than a billion dollar car brand funding a team of researchers who went to university for years to be the best at what they do.


And it's even funnier when you tell me to keep learning.

[chris719]

Originally Posted by Westersund

According to Motul's website they recommend DCTF for the MT and DCTF High Torque for the DCT. But I'm sure the High Torque works as well. I use the regular Motul DCTF in my car and it works just as well as with the stock oil.

Yeah, as F87Source mentioned I contacted Motul. Their rep told me that the lack of MT recommendation for High Torque DCTF was because they are planning to introduce a version of that fluid that uses less expensive friction modifiers and target it toward manual transmission use. They seemed to be saying that the friction modifiers the DCTFs use are overkill for MTs.

[vrooooom]

Anyone can say and claim anything on the Internet, all I know is F87 follows (to the dot and I wholly appreciate that) what the manufacture says and everything else is up to whoever wants to follow ....or not (the consequence as a result is his alone). IMHO, it's quite irresponsible to say that the "Diff plugs can be used without O-ring". Why take risk like that w/ a consequence of f-ing up your diff completely? Buy a new bolt, replace o-ring w/ viton or chk and re-use but to use without....craziness.

[David.m]

Originally Posted by Track/S

Bmw does very stupid things, such as using an o-ring in the diff and not using it in the gearbox, or mounting crankhub without keying...
The diff plug o-ring is completely unnecessary.

Curious, was it this same reasoning that led you to replace a structural piece of the front suspension/chassis with a part designed to improve aero? You never updated your thread so can only assume you're still driving around with the stiffening plate lying on the garage floor........

[vrooooom]

Let him, so long as he doesn't take anyone w/ him due to that decision. Democracy. To each his own, etc etc. Reminds me so much of an "accident" that went all over the news worldwide though. Admittedly I'm one of those that re-used the one-time use bolts on the stiffener plate.

[Westersund]

Originally Posted by chris719

Yeah, as F87Source mentioned I contacted Motul. Their rep told me that the lack of MT recommendation for High Torque DCTF was because they are planning to introduce a version of that fluid that uses less expensive friction modifiers and target it toward manual transmission use. They seemed to be saying that the friction modifiers the DCTFs use are overkill for MTs.

Was it a sales rep or a tech rep? I'm sure the High Torque version works, but I'm sticking to the regular DCTF in my gearbox. The reason a DCT gearbox needs the friction modifiers (much like a clutch style differential) is to lubricate the clutch packs to make them slip more for smoother gear changes. The regular manual gearbox on the other hand has synchros to equalize the revs inbetween shifts and if you have friction modifiers that makes the oil more slippery the synchros can't equalize the revs as well. But it's all degrees in hell, how much is too much etc. If you have tried and it works all is good.

[doughboy]

I'm thinking I'll get the redline anyway?

I read that's a full synthetic but the Motul is a blend.

But if i go Motul I'll stick to the one that says MTF on it.

[F87source]

Originally Posted by doughboy

I'm thinking I'll get the redline anyway?

I read that's a full synthetic but the Motul is a blend.

But if i go Motul I'll stick to the one that says MTF on it.

I'd go redline (and actually will go redline on my next 6mt oil change), I heard a lot of really good stuff about it and how it significantly improves shift feel, but I haven't heard anything about the motul.

[Westersund]

Originally Posted by doughboy

I'm thinking I'll get the redline anyway?

I read that's a full synthetic but the Motul is a blend.

But if i go Motul I'll stick to the one that says MTF on it.

I use Motul DCTF (Not High Torque) and it works great, doesn't matter which one you chose both will perform great.

[chris719]

Originally Posted by Westersund

Was it a sales rep or a tech rep? I'm sure the High Torque version works, but I'm sticking to the regular DCTF in my gearbox. The reason a DCT gearbox needs the friction modifiers (much like a clutch style differential) is to lubricate the clutch packs to make them slip more for smoother gear changes. The regular manual gearbox on the other hand has synchros to equalize the revs inbetween shifts and if you have friction modifiers that makes the oil more slippery the synchros can't equalize the revs as well. But it's all degrees in hell, how much is too much etc. If you have tried and it works all is good.

It was their Technical Support Manager for NA, Nicolas Demaria. I haven't made the swap yet, but TopJimmy on the F8x forum had been using it in his 6MT for a while. He said it was the only fluid that cured his synchro grind when drag racing.

[kthor703]

Just did my trans and diff fluid swap today. I tried to level the car as best as I could. Ended up taking just under 1L for the Diff and the 1.3-1.4L for the trans.

Interestingly, a service manual service I have access to through work listed 1.6L estimated for the trans (opposed to the 1.3L I keep seeing). Regardless, the car took closer to 1.3L...found that interesting.

[F87source]

Originally Posted by kthor703

Just did my trans and diff fluid swap today. I tried to level the car as best as I could. Ended up taking just under 1L for the Diff and the 1.3-1.4L for the trans.

Interestingly, a service manual service I have access to through work listed 1.6L estimated for the trans (opposed to the 1.3L I keep seeing). Regardless, the car took closer to 1.3L...found that interesting.

Your service manual is likely wrong, ISTA specifies 1.3L. 1.6L could be a dry fill for a brand new transmission - but I doubt it as ISTA didn't list any other fill capacity.


But generally a rule of thumb is on level ground just fill until it overflows from the fill port.

[doughboy]

Originally Posted by TheHaze

Nope, I was never able to source it. SAF-XJ is what the dealership used for the 1,200 mile break-in service and it's what I plan on using when I service it myself in a couple months.

If you want MSP/A it's all over ebay in the UK, up to you if you want to pay shipping though.

[doughboy]

Originally Posted by kthor703

Just did my trans and diff fluid swap today. I tried to level the car as best as I could. Ended up taking just under 1L for the Diff and the 1.3-1.4L for the trans.

Interestingly, a service manual service I have access to through work listed 1.6L estimated for the trans (opposed to the 1.3L I keep seeing). Regardless, the car took closer to 1.3L...found that interesting.

Was it warm/hot when you drained it? if cold its quite thick and slower to drain.

[doughboy]

Looking at the Motul race gear LSD oil that's 33% more expensive in UK than genuine MSP/A.

Maybe worth it for funky blue colour though