X5 4.4 - Sludge in engine and oil filter housing... help!

[m5james]

...which basically says to either change it every 50k (which I've suggested since day one) or play the odds and leave it be. For those who haven't changed it, then it's on you and it's simply a choice after that. Some have had luck changing the fluid in the 100k range w/ no ill effects and reported better shifting. Some have even changed fluid when they had shifting issues and it solved the problem. Some have also changed the fluid and had failures within days, weeks or months. It seems there is no definate answer, but since I've had no issues changing at 50k, which I've always done, then it's my conclusion that it shouldn't be an issue as long as it's maintained sooner than later, not waiting till issues have already risen.

[JCL]

Originally Posted by X5 Meister

Yeah but they went in the opposite direction with the coolant and you can ask the same question !?

You can't correlate oil, trans fluid, coolant, and brake fluid, and say that they all have the same issues. They don't. They have different failure modes, entirely different compositions and purposes, and so on.

Lifetime coolant, to me, means it had more additives in it to prevent foaming, etc. While you could leave it in for a very long time, changing it every four years seems reasonable, given that there is no real downside. Maybe they decided that water pumps go out after 5-6 years, and that is the definition of coolant lifetime, I don't know.

Strictly as an example, if you leave your brake fluid for four years, you will likely experience stuck calipers (see the recent posts on the subject, likely related to vehicles where owners ignored the two year flush interval).

I don't understand why different fluids are being directly compared.

[JCL]

Originally Posted by sunny5280

It's a foolish explanation. What he's saying is BMW decided, for marketing purposes, to recommend a proceedure alleged to cause transmission failure.

BMW decided, for marketing purposes, to sell M vehicles in a country with 65 mph speed limits. Speeding is a procedure alleged to cause bodily harm. However, they probably figured they could move a few vehicles, and make a dollar. Good for them. What was your point?

[sunny5280]

Originally Posted by JCL

BMW decided, for marketing purposes, to sell M vehicles in a country with 65 mph speed limits. Speeding is a procedure alleged to cause bodily harm. However, they probably figured they could move a few vehicles, and make a dollar. Good for them. What was your point?

My point is, if we're told hold your assertion true to any reasonable degree, then BMW is recommending to their customers a needless proceedure that will result in transmission failure. Do you really think they'd do that for marketing reasons?

[sunny5280]

Originally Posted by JCL

Lifetime coolant, to me, means it had more additives in it to prevent foaming, etc. While you could leave it in for a very long time, changing it every four years seems reasonable, given that there is no real downside. Maybe they decided that water pumps go out after 5-6 years, and that is the definition of coolant lifetime, I don't know.

"No real downside" implies there is some downside. So, like replacing the transmission fluid, why would you risk it?

[JCL]

Originally Posted by sunny5280

From my second post on this subject I clearly said:

"There is the possibility of dislodging sediment but even if that were the case I have seen no evidence to support that dislodged sediment correlates to transmission failure....."

"I previously acknowledged the possibility of disloding sediment....... Furthermore should sediment be dislodged I have seen no evidence it will result in a transmission failure.

You've got it backwards. The only way you would know sediment was dislodged, and that it mattered at all, is when you do have a transmission failure. You are saying that there can be sediment moved, but so what? I am saying that the failure analyis of any failed transmission provides the type of proof you are looking for. Think about the valve body located in the pan of the transmission. It contains very small orfices, check valves, and control circuits. The failure analysis of a transmission that didn't shift properly (after a fluid change) has been found on too many occasions to include that famous sediment in the valve body, restricting a passageway. It isn't that sediment might get dislodged, and not hurt anything. We wouldn't even know if that happened. It is that if you analyze a failed transmission, and check which clutch pack or actuator stopped working, and then search for and find debris in that circuit that you can conclude that something caused the debris to move.

The photo attached isn't a ZF, but it will do. There is a spool valve at the top left, and there are multiple check valves (ball bearings with springs). The passageways are about the size of a pencil lead. Also, the fluid is somewhat static, so what gets stuck doesn't get flushed out easily.

Sorry, that is the best I can do for an explanation. Photo attached.

[Penguin]

Originally Posted by JCL

BMW decided, for marketing purposes, to sell M vehicles in a country with 65 mph speed limits. Speeding is a procedure alleged to cause bodily harm. However, they probably figured they could move a few vehicles, and make a dollar. Good for them. What was your point?

That's a slippery slope to start on -- if BMW can change their AT fluid change recommendation from Lifetime to 100,000 for marketing reasons, even if it is unwise to change ATF for the first time at 100,000, then who's to say they didn't originally change it from 50K to Lifetime for marketing reasons, even if that was unwise?

Once one accepts that BMW maintenance requirements and intervals are influenced by Marketing, and not just Engineering, it sort of kills the argument that "BMW Knows Best" when it comes to maintenance requirements.

[JCL]

I'm still waiting to see where BMW changed their recommendations for fluid changes. They never did with any BMW that I owned. I can't imagine them wanting to take on the liability if they did want to change the interval.

What they did do was come out with newer models, with new transmissions, with new fluid specifications, which have different change intervals than previous models. Those posters who never liked the old recommendations have adopted the new ones, even for older vehicles. To me, that is like doing 15,000 mile oil change intervals on an older vehicle that was designed for 7500 mile intervals. It is cherry picking. The recommendations that matter apply to the specific vehicle in question.

Now, does marketing have a part in all this? Certainly, as they will have suggested to the engineers that it would be great if they could advertise lower maintenance costs. But to claim that marketing made that decision without any say from engineering at all seems silly. Look at Meisters post above about the engine-specific recomendations now coming out. I don't think marketing has much of a role in those decisions.

[JCL]

Originally Posted by Penguin

It sort of kills the argument that "BMW Knows Best" when it comes to maintenance requirements.

I certainly don't think that BMW knows best about all maintenance practices. I think they have a good framework, a good starting point. Those who don't agree with BMW recommendations accuse some of us of blindly following BMW guidelines. Personally, I like to understand the guidelines, use them as a starting point, and go from there.

When BMW first said not to rotate tires, many years ago, I was suspicious. I had rotated tires for decades. So, I watched my tires very closely, and had over 70,000 km on the original tires, with very even wear, when I sold the vehicle. So, I guess they were right. Sometimes we have to adapt our thinking.

[sunny5280]

Originally Posted by JCL

You've got it backwards. The only way you would know sediment was dislodged, and that it mattered at all, is when you do have a transmission failure. You are saying that there can be sediment moved, but so what? I am saying that the failure analyis of any failed transmission provides the type of proof you are looking for. Think about the valve body located in the pan of the transmission. It contains very small orfices, check valves, and control circuits. The failure analysis of a transmission that didn't shift properly (after a fluid change) has been found on too many occasions to include that famous sediment in the valve body, restricting a passageway. It isn't that sediment might get dislodged, and not hurt anything. We wouldn't even know if that happened. It is that if you analyze a failed transmission, and check which clutch pack or actuator stopped working, and then search for and find debris in that circuit that you can conclude that something caused the debris to move.

The photo attached isn't a ZF, but it will do. There is a spool valve at the top left, and there are multiple check valves (ball bearings with springs). The passageways are about the size of a pencil lead. Also, the fluid is somewhat static, so what gets stuck doesn't get flushed out easily.

Sorry, that is the best I can do for an explanation. Photo attached.

Again you're arguing as if I've made the argument that it will never happen. That's not the case. As the post you responded to shows I've clearly acknowledge it can happen. So will you please stop tearing down that strawman of yours?

With that said I have seen no data to correlate transmission failure with fluid replacement. You say you have some but when asked to provide it you balked. You're own qualification of it happening is "slight". You can't say it's slight and then argue it's more than slight. Pick a side and stick with it.

The fact you've seen transmission failures shortly after the fluid was changed doesn't automatically translate into the fluid change being the cause. There are many factors which could have resulted in the failure. From your own argument some of those factors could be: Incorrect fluid and improperly performed work. Other factors include an owner attempting to fix a more severe problem with a fluid change. I would suggest this latter being more common than a fluid change resulting in the failure. Or maybe the thing was just going to break regardless of the fluid change. Without any data we can't narrow it down to any one specific reason.