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

[sunny5280]

Originally Posted by faz

I actually read through almost all of this thread.

This is a really good thread, in that, anyone who doesn't have a firm opinion on whether they should or should not change their transmission fluid (especially at a high mileage), ... who ends up finding this thread through a search and reads through this thread.... will most definitely NOT change the transmission fluid, based on the materials presented by both sides AND the manner in which they were presented.

Then they would being doing so against sound advice and favoring an urban legend.

[Penguin]

Originally Posted by sunny5280

Then they would being doing so against sound advice and favoring an urban legend.

Well, I probably should just drop this, but why is that any more of an "Urban Legend" than the "Urban Legend" that changing your AFT will make your transmission last longer?

I guess I am saying that the term "Urban Legend" is a bit strong and misleading in that context. I would position it more as "debatable and supported only through anecdotal reports, which are not statistically significant."

Which could also be said of the other side of the argument.

P.S. I promise to shut-up about this topic after this post.

[sunny5280]

Originally Posted by Penguin

Well, I probably should just drop this, but why is that any more of an "Urban Legend" than the "Urban Legend" that changing your AFT will make your transmission last longer?

Arguments pro "change the ATF":

• BMW recommends it at 100K mile intervals.
• No fluid is lifetime. Lifetime being defined as never change.
• Fluids act as a detergent and become dirty with use.
• The protective qualities of lubricants breaks down over time.
• Every other fluid in the vehicle is subject to change at regular intervals.
• Other vehicle manufacturers recommend ATF changes.

Arguments con "change the ATF":

• In 2002 Mike Miller, head technical editor of BMWCCA, made the recommendation to avoid ATF changes due to his observed increase in subsequent transmission failures.
• Numerous web sites making the same recommendation as Mr. Miller.

So we have facts for pro "change the ATF" (I put this in quotes because my argument has never been to change the ATF but more it doesn't hurt to do it) and opinions on the con "change the ATF".

In 2009 Mr.Miller appears to have reevaluated his 2002 recommendation and no longer has the passion for it he once had (but does continue to say there is a risk). As for the numerous web sites I suspect they picked up on Mr. Millers 2002 recommendation and ran with it. And now discussions on this subject make references to one another (it happened in this one) in a form of circular support (I've seen this happen too many times).

Many disagree with my urban legend label but that's how I view it. An unsupported claim has been made and repeated ad infinitum and taken on a life of its own. So much so that people making it feel threatened when someone dare question it.

[JCL]

Originally Posted by sunny5280

Arguments pro "change the ATF":

• BMW recommends it at 100K mile intervals. Which coincidentally, is when your warranty is over. They don't want you changing it during the warranty period. Once that is over, any failure is at your risk. Of course, they would never be that calculating.
• No fluid is lifetime. Lifetime being defined as never change. This is a position, not an argument.
• Fluids act as a detergent and become dirty with use. Actually, the ATF includes detergent additives. When those additives are all gone, it would be a reasonable time to change the fluid. The fluid gets dirty, but that is why there is a filter.
• The protective qualities of lubricants breaks down over time. Well, oil never stops being slippery, the lubrication qualities never fade away. The fluid does need to be incompressible (to work the actuators), and to be a heat conductor. There are additives to prevent foaming, and friction modifiers for the clutches. So, if the additives are depleted, the fluid could benefit from being changed. However, those very high mileage transmission being reported (on original fluid) suggest that the additives do in fact last a very long time. Perhaps even the component's lifetime.
• Every other fluid in the vehicle is subject to change at regular intervals.How about your AC refrigerant (which lubricates the compressor), or the grease in the CV joints. They are lifetime too. I suggested shock absorbers before, but that got shot down. How about universal joints? Tie rod ends? Ball joints? Steering shafts? All things that used to be lubricated before we went to lifetime lubrication. There are not many places to use a grease gun on a modern vehicle any more.
• Other vehicle manufacturers recommend ATF changes. That would be a good reason to follow their recommendations, to keep your warranty valid. But aren't we talking about BMWs here?

Arguments con "change the ATF":

• In 2002 Mike Miller, head technical editor of BMWCCA, made the recommendation to avoid ATF changes due to his observed increase in subsequent transmission failures.
• Numerous web sites making the same recommendation as Mr. Miller.
• Numerous mechanics and BMW technicians making the same recommendation.

Comments included above in red.

I should clarify that I don't necessarily think that ATF should never be changed, or that it should always be changed. I do think that readers should make their minds up after understanding the risks and rewards. There is no conclusive data either way. There are reasons to change the fluid, and reasons not to. Readers making an informed decision after understanding the two sides is far better than blindly changing it because it is somehow supposed to be done.

[X5 Meister]

When this post hits 1,000 I am going to personally call the Castrol dipstick guy to come to each of your homes and whip you on the back of the legs.

[Weasel]

Simply put, I will be changing my fluid and filter at the same time I change the friction materials or other components in my transmission.

Regardless of whether you change the fluid every 100,000 60,000 or 3,000 miles the friction material on the plates will inevitably wear, as will the electronic solenoids/valves and the rubber components. The fluid does break down over time, but the nice expensive synthetic fluids used in modern transmissions like in BMWs lasts a really long time before losing its lubricating and hydrolic properties.

If the fluid was overheated by repeatedly towing heavy loads then it can lose it's viscosity and should be changed, or if you have a component fail that spreads metalic debris that suspends in the fluid and clogs the filter. Lots of times the metal particles are tiny enough to flow through the filter and stay suspended in the fluid which is bad for all other moving parts.

The reason transmissions can fail if the fluid is changed at a higher mileage is simply because the worn off friction material is tiny enough to flow through the filter and stays suspended in the filter, adding to the viscosity of the fluid which adds hydrolic pressure, as well as adding to the friction between the plates. When you change all that fluid with fresh new fluid the extra friction/grip in the plates is gone and replaced with fresh slick fluid as well as slightly lower hydrolic pressures pushing against the plates... which all adds up to cause slippage, thus transmission failure needing rebuilding.

There is no proof or solid documentation depicting this because each and every transmission will be an individual case of wear and other variables due to the use and driving styles of different people. If you are considering whether or not to change your transmission fluid I would strongly suggest taking a small sample of about half a pint or so to inspect. You can look at it stirring it under bright light to inspect for presence of worn metal components. (will look like metal flake in a paint job) Same for presence of clutch material. (dull gray material, like graphite powder) as well as smell the fluid to see if it smells like tranny fluid (kind of a gear oil smell in BMW's case with the lifetime fluid) or if it smells burnt from overheating/overworking.

Basically you should look at the fluid in each individual case and get as many facts as possible from the fluid in each particular case to get a better idea, and thus make a judgment call from knowledge, not blind beliefs.

my 0.2c over

[X5 Meister]

This thread has really grown by leaps and bounds, fortunately however, buried within it is some really great information. One of the best posts, if not THE best IMHO, is #180 above by Weasel. I agree with basically everything he is saying, but at the same time I want to throw in a few of my own comments / observations into the mix.

1. BMW recommends 100,000 mile transmission fluid changes, not "lifetime" which actually is a recommendation for other other fluids such as coolant. (Now let's forget for a minute what is the motivation behind this recommendation) The caveat is that this recommendation applies to transmissions that were operated under "normal conditions." What constitutes "normal" I personally have no idea. Is it me driving a car or my grandmother? Further, in the case of a vehicle specifically designed to go off road, tow up to 6,000 lbs, and yet still perform like a sports car, I REALLY have no idea what is "normal!" In any case, the recommended fluid change interval is in fact different for an X5 driven in not-normal conditions (let's put it that way).

2. The multitude of problems that come with trying to define normal / not-normal situations are pretty obvious. So here's just one example. If you bought your car used, who knows how the previous person drove it? Maybe they pulled a trailer every day up until the point of sale? Maybe they thought they were Michael Schumacher (though not the current dude in F1)? Or maybe they drove to Bergdorf's every other day for shopping? All 3 of which I would consider not-normal, for differing reasons. Since you don't know for certain, perhaps an early fluid change is the way to go? And since you really DON'T know, perhaps an early fluid change at ANY mileage is the way to go?

3. In something I read, ZF seems to back point #2, however they state that looking at the fluid should be your guide. Last time I checked, my eyeball did not contain a microscope and built-in fluid analysis equipment to make an educated determination on fluid composition. Few people have JCL's experience in this stuff and so unless the fluid is burnt to a crisp, I don't know any one of us normal people who would know if indeed the fluid needed changing or not without some sort of detailed lab report to go by. Interestingly ZF recommends that the fluid be changed when it smells burned, however "the damage is already done." Nice one.

4. On their website, (see attached screen shot photo) they discuss their LifeGuard Fluid 6 (which is a special fluid blended by Shell for ZF; Shell calls it M1375.4; see photos) as offering extended maintenance intervals to 100,000 km / 62,000 miles. Interesting. This is certainly no 100,000 miles / 162,000 km recommendation. So if an EXTENDED maintenance interval on this fluid (which is after all the OE fluid and the ONLY fluid recommended for this gearbox) is 62,000 miles then perhaps driving in not-normal circumstances would warrant fluid changes at intervals shorter than 62,000 miles?

5. The transmission maintenance recommendations from ZF (see attached fluid recommendations and interval recommendations below) have some different information. Here they indicate that should not-normal (my words) conditions exist, maintenance intervals should be as low as 80,000 km (49,600 miles) or as high as 120,000 km (74,400 miles) or 8 years. So now what does this mean? If you don't have a clue how your transmission was treated should you have the fluid changed at 49,600 miles? How about if you have 25,000 miles and your car is 8 years old? Are they saying that the fluid is now sufficiently broken down to warrant changing?

6. In a letter from ZF circulated to shops (see attached) it discusses "lifetime fill" and leaves it up to the car manufacturers' to decide what that means, however it does address the notion of what I am calling not-normal conditions. In such conditions it calls for 100,000 km or 8 year fluid changes. Yet another different recommendation!

7. Given all the above, the way I understand the recommendations is that the best option is to have a fluid analysis done in order to determine whether or not a fluid change is necessary. A company like Blackstone Labs (no I don't work for them) might be the best option, see attached sample report (thanks to the original poster of it in a different thread).

I don't have any of the answers, just wanted to post some of what I had discovered on this clearly complicated matter.

Confused yet?

[JCL]

Originally Posted by X5 Meister

This thread has really grown by leaps and bounds, fortunately however, buried within it is some really great information....

Meister, good background info.

A couple of comments to muddy the waters (fluid) further:

We keep discussing miles (or km) here when in fact that is not likely to be the best predictor of life. I have experience with heavy duty off highway transmissions in haul trucks and other applications. These trucks (up to 400 ton capacity) have a form of automatic transmission, and mechanical drive, not electric drive. As the trucks got larger, and when we got up to 2000+ hp (they are now up over 3500 hp) the impact of a failure was so extreme that the monitoring of components like transmissions got very precise.

We had traditionally measured component life by hours (since these are low speed applications, up to 60 km/hr). What emerged was that there was a better indicator than hours, or truck load, or grade, and that was the number of transmission shifts. It became a predictor for transmission component exchange intervals. On a long haul road out of a deep mine pit, the trucks would sometimes shift at every cross road, as the effective grade changed. That caused early transmission failure. It turned out that the grade didn't matter as much as the consistency of the grade.

We would have fleets of 20-50 trucks, at each of 10-20 minesites, and so could produce good analytic data (which we can't really do with over the road vehicles, where we have anecdotal reporting at best).

The point of all this is that just like with heavy equipment, the number of transmission shifts is likely to be an indicator of failure. Driving on the highway in 5th or 6th for 100,000 miles is nothing like driving in city traffic for 100,000 miles, and I think that this multiplier is far more than it would be for trailer towing, or spirited driving, which you mention.

Second point is about fluid sampling. I am a big fan of fluid analysis, have worked in a fluid analysis lab, and used it for years. The company I worked for had a very large lab (not Blackstone) That said, it has limited value when applied to cars. That is simply because the value is in trending the results, preferably with a fleet. Point samples are virtually useless. Many car owners do one, or two samples, and use it to justify what they already believe to be true. Other vehicles can't be compared to theirs, due to different duty cycles, driving conditions, fluids, etc. An oil sample can find water, or antifreeze, and that is valuable. It can measure TBN, which if trended can show additive life. It can measure viscosity, but you need to know what the acceptable viscosity is to make that valuable. Unfortunately, what usually happens with oil samples is that people focus on the metals found through spectrometry, which are dissolved in any case. Those results are telling you about your engine (or transmission), not about your oil, in most cases, unless you are paying additionally for large particle analysis with your oil sample.

Edit: I just had a look at the attached sample, and I think that it supports this. There is no detailed information on the results expected for the specific transmission (they don't even note who made the transmission, so how could they?) The universal averages are for an indeterminate population. The viscosity is (surprise) within spec for both measures, yet there is a recommendation to change the fluid based on elements found in the fluid that may have been there since break in. I wonder if that copper came from the clutch plates, or if there is perhaps a cooler in this system that could have provided the copper over the last 83,000 miles? And then with all that inconclusive data, the interpreter advises to change the transmission fluid after 10,000 -15,000 miles. That doesn't seem to be a supported recommendation based on the sample results as reported. This just shows the cautions needed when using fluid analysis, which is in general good science.

[X5 Meister]

Excellent points, and particularly interesting real world examples I must say.

I agree with your thoughts on fluid analysis and that, just like in virtually every science, multiple data points are preferred if one is to make any educated guess on the future based on prior results. I think what Blackstone is in reality saying in their assessment is that they need more data points to see what is really going on. And much like you said, an analysis at another relatively short mileage would help answer (somewhat at least) the question as to when some of the particulates are appearing in the fluid; at break in a long time ago or relatively recently.

What I do find interesting is that ZF seems to be implying that since modern fluids are quite stable and have the ability to hold particles in suspension for longer periods of time, that failures caused by fluid changes shouldn't happen... at least up to a point. The question is just what is that point... 80,000km, 100,000km, 120,000km, 100,000 miles or 8 years?

Your heavy equipment example got me thinking. What would be an interesting thing to look at is what other car manufacturers that use the same transmission and fluid recommend. It won't be a perfect comparison, because those manufacturers (Audi, Bentley, Hyundai, Land Rover, Jaguar, Maserati, etc) will all have different software to operate the transmissions differently from BMW, however what would be fascinating to know is what Maserati, for example, thinks in terms of fluid change intervals on a ZF 6HP26 transmission used under their definition of "normal" conditions in a sports car versus Jaguar who might use it in a luxury saloon, versus Land Rover who uses it in a true SUV, versus Hyundai who uses it in their whatever mobiles?

[chefwong]

I'd like to chime in on my recent drain interval on such a hotly debate. YMMV, and I would think twice about changing fluid if you are in the higher mielage and do not know the previous mechanical history

At 75K, this would probably be my 3rd fluid change - maybe even 4th. Too lazy to look at my records...Fluid is CHEAP to me. I have done 1 drain bolt as well as a a pan drop. At 75K, I just did another drain bolt. I was having some weird noticeable slight lag issues upshifts to 3rd gear. It's not a placebo effect but refreshed fluid did make that go all go away FWIW.