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

[sunny5280]

Originally Posted by FSETH

That is the thing though, if you change it from early on, I think it is better. If you wait until 100k+ and change it for the first time, you are running the risk of dislodging sediment (whatever else) and that is something that can potentially cause issues on higher mileage transmissions. Not saying it will happen, but can. There are enough threads on this topic floating around to keep you busy for days on end.

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. So while the risk is there I think a transmission failure resulting from it is so rare as to make it a non-issue.

[FSETH]

Originally Posted by sunny5280

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. So while the risk is there I think a transmission failure resulting from it is so rare as to make it a non-issue.

I found this post from JCL in one of the numerous trans fluid threads...

On higher mileage transmissions it isn't the metal shavings you have to worry about, although there could be some. If you have metal shavings, it doesn't really matter if you change the fluid or not as the transmission is likely on its way out. What wears inside a transmission are the clutch packs (multi-disk wet clutches) and the bands; both are surfaced with a non-metallic friction material that wears over time. That material is what can clog a valve body. It sits there undisturbed but can be moved by a fluid change. Clean fluid doesn't dissolve it, but draining the fluid and then starting it up and repressurizing the clutch packs can move it around. It may not happen, but in any case that is the theory behind the risks of changing fluid on high mileage transmissions.

I am going to jump off the JCL train now. I am not saying this is going to happen, but I guess I wouldn't call it a non-issue either.

[sunny5280]

Originally Posted by FSETH

I found this post from JCL in one of the numerous trans fluid threads...

On higher mileage transmissions it isn't the metal shavings you have to worry about, although there could be some. If you have metal shavings, it doesn't really matter if you change the fluid or not as the transmission is likely on its way out. What wears inside a transmission are the clutch packs (multi-disk wet clutches) and the bands; both are surfaced with a non-metallic friction material that wears over time. That material is what can clog a valve body. It sits there undisturbed but can be moved by a fluid change. Clean fluid doesn't dissolve it, but draining the fluid and then starting it up and repressurizing the clutch packs can move it around. It may not happen, but in any case that is the theory behind the risks of changing fluid on high mileage transmissions.

I am going to jump off the JCL train now. I am not saying this is going to happen, but I guess I wouldn't call it a non-issue either.

I previously acknowledged the possibility of disloding sediment. However my personal opinion, and it appears it is shared by JCL, is the possibility of it happening is very low. Furthermore should sediment be dislodged I have seen no evidence it will result in a transmission failure. So the chances of dislodging sediment are very low and the chances of dislodged sediment resulting in a transmission failure are very low.

[JCL]

Originally Posted by sunny5280

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. So while the risk is there I think a transmission failure resulting from it is so rare as to make it a non-issue.

My largest concern is with moving sediment around upon repressurizing clutch packs, solenoids, etc. It is a classic failure mode for transmissions that otherwise work fine, have no apparent problems, get a fluid change and then fail soon after. If you don't think it is a risk, then you should change the fluid. We aren't talking absolutes here, whereby every fluid change causes a subsequent failure, just a risk profile, whereby there are many failures that can be attributed to fluid changes.

The other risk is that the fluid has changed viscosity over time, and when you put new (thinner) fluid in, it doesn't work as well due to being thinner. The transmission adapts to different fluid characteristics over time.

FSETH actually saved me a lot of typing, thanks bud!

[sunny5280]

Originally Posted by JCL

My largest concern is with moving sediment around upon repressurizing clutch packs, solenoids, etc. It is a classic failure mode for transmissions that otherwise work fine, have no apparent problems, get a fluid change and then fail soon after. If you don't think it is a risk, then you should change the fluid. We aren't talking absolutes here, whereby every fluid change causes a subsequent failure, just a risk profile, whereby there are many failures that can be attributed to fluid changes.

This is just a restatement of the post FSETH linked to. There you said you felt the chances of dislodging sediment are slight. I agree with this. There is a possibility but I don't see it being very high. Nor do I see any evidence the dislodged sediment, in the slight case it occurs, results in transmission failure.

The other risk is that the fluid has changed viscosity over time, and when you put new (thinner) fluid in, it doesn't work as well due to being thinner. The transmission adapts to different fluid characteristics over time.

I am assuming you're replacing the fluid with the recommended fluid. Which makes this point moot.

[JCL]

Originally Posted by sunny5280

This is just a restatement of the post FSETH linked to. There you said you felt the chances of dislodging sediment are slight. I agree with this. There is a possibility but I don't see it being very high. Nor do I see any evidence the dislodged sediment, in the slight case it occurs, results in transmission failure.


I am assuming you're replacing the fluid with the recommended fluid. Which makes this point moot.

It is not just a restatement. The chances of a fluid change causing a transmission to fail are slight, but still very real. You have to weigh that against the benefits of clean fluid. What makes you think that clean fluid will make the transmission last longer? There is no data to support that point of view. I say the chances are slight, because posters regularly change their fluid, don't have a failure, and then conclude that this is proof it was a good idea. It isn't proof, it is simply proof that they dodged the bullet, and good for them in that case. I won't change my own transmission fluid because I see no reason to. The transmission failures we have seen haven't been caused by worn out fluid.

Talk to anyone who has worked in a transmission shop, and they will confirm that they regularly get overhauls caused by unneeded fluid changes. Doesn't happen with every fluid change, but it is a very common failure mode. Sludge that wasn't hurting anything gets flushed into the valve body when you refill it and restart it, on the initial pressurization; that sludge then clogs an orfice, and causes an actuator or sensor to fail.

If you are replacing the fluid, I assume you are using the correct fluid specification. That doesn't make my point moot, however, as fluid changes viscosity over time. That is known to the engineers, and the transmission adapts to the fluid as it ages. There are feedback sensors on things like clutch delays, etc. When you put thinner (correct, but still thinner) fluid in, you can get failures. Again, transmission mechanics are familiar with this. It has been discussed on this site by BMW techs.

All of this said, do whatever makes you happy. If you think you want to change the fluid, just change it. If it causes a transmission failure, you can always tell yourself that it was going to happen anyway, and that you didn't initiate it. If it doesn't fail, you win as well.

[sunny5280]

Originally Posted by JCL

It is not just a restatement. The chances of a fluid change causing a transmission to fail are slight, but still very real. You have to weigh that against the benefits of clean fluid. What makes you think that clean fluid will make the transmission last longer? There is no data to support that point of view. I say the chances are slight, because posters regularly change their fluid, don't have a failure, and then conclude that this is proof it was a good idea. It isn't proof, it is simply proof that they dodged the bullet, and good for them in that case. I won't change my own transmission fluid because I see no reason to. The transmission failures we have seen haven't been caused by worn out fluid.

We're in agreement there is a slight risk accumulated sediment can be dislodged. However I have seen no evidence to suggest dislodged sediment results in significant numbers of transmission failures. Therefore, in the absense of data to the contrary, the risk is so minimal as to make it a non-issue.

As to the benefit lubricants breakdown and become dirty over time and their ability to provide the protection they once did is reduced. Thus increasing wear on the components.

Given this I believe replacing the fluid has benefit that far exceeds the risk.

Talk to anyone who has worked in a transmission shop, and they will confirm that they regularly get overhauls caused by unneeded fluid changes. Doesn't happen with every fluid change, but it is a very common failure mode. Sludge that wasn't hurting anything gets flushed into the valve body when you refill it and restart it, on the initial pressurization; that sludge then clogs an orfice, and causes an actuator or sensor to fail.

I spoke with my mechanic about this and he recommends replacing the transmission fluid at regular intervals. As a matter of fact I had never heard of transmission failures resulting from fluid changes until I started reading BMW forums. I have seen no data to support changing the oil correlates into any significant number of transmission failures. Your reasoning makes sense but I think it is applicable in only a small number of cases.

If you are replacing the fluid, I assume you are using the correct fluid specification. That doesn't make my point moot, however, as fluid changes viscosity over time.

If you use the correct fluid why would the viscosity be relevent?

That is known to the engineers, and the transmission adapts to the fluid as it ages. There are feedback sensors on things like clutch delays, etc. When you put thinner (correct, but still thinner) fluid in, you can get failures. Again, transmission mechanics are familiar with this. It has been discussed on this site by BMW techs.

All of this said, do whatever makes you happy. If you think you want to change the fluid, just change it. If it causes a transmission failure, you can always tell yourself that it was going to happen anyway, and that you didn't initiate it. If it doesn't fail, you win as well.

This is a specious conclusion. If, after changing the fluid, the transmission fails how do you know it wasn't about to fail regardless? I think we're all aware of people who, in a desperate attempt to avoid a rebuild/replacement a transmission, hope changing the fluid will fix a symptom of a failure. Conversely if the transmission doesn't fail how do we know it was luck and not preventative maintenance?

[JCL]

Originally Posted by sunny5280

We're in agreement there is a slight risk accumulated sediment can be dislodged. However I have seen no evidence to suggest dislodged sediment results in significant numbers of transmission failures. Therefore, in the absense of data to the contrary, the risk is so minimal as to make it a non-issue.

Have you ever worked overhauling transmissions? I suspect not. It isn't a non issue to those of us who have, but it may be to you. That's cool.

Originally Posted by sunny 5280

As to the benefit lubricants breakdown and become dirty over time and their ability to provide the protection they once did is reduced. Thus increasing wear on the components.

No argument. Only issue is, is it relevant? Are X5 transmissions failing due to lubricant quality? Not according to the posting history on this board and others. Sensor failures, actuator failures, programming failures, are all unrelated to fluid quality. They are at the root of many early transmission failures. Changing the fluid won't improve your odds.

Originally Posted by sunny5280

Given this I believe replacing the fluid has benefit that far exceeds the risk.

Then you should change your transmission fluid. You are the only one who will live with the consequences, so just do it.

Originally Posted by sunny5280

As a matter of fact I had never heard of transmission failures resulting from fluid changes until I started reading BMW forums. I have seen no data to support changing the oil correlates into any significant number of transmission failures. Your reasoning makes sense but I think it is applicable in only a small number of cases.

My reasoning is based on working in a shop. I can't tell you what to do, just that I won't change my own transmission fluid. I do believe in preventative maintenance. I just believe that in the case of the X5 transmission, the risks outweigh the benefits.

Originally Posted by sunny5280

If, after changing the fluid, the transmission fails how do you know it wasn't about to fail regardless? I think we're all aware of people who, in a desperate attempt to avoid a rebuild/replacement a transmission, hope changing the fluid will fix a symptom of a failure. Conversely if the transmission doesn't fail how do we know it was luck and not preventative maintenance?

I wasn't referring to those cases. I was referring to the multiple cases where a transmission worked fine, up until soon after it had the transmission fluid changed. It happens too often. Technicians in transmission repair shops know about it. You can discount it if you like. It is the reason that those of us who have rebuilt transmissions make judgement calls on whether to change the fluid in this case. I think there is a small chance of a fluid change causing a failure, overall. I think there is even less likelihood of degraded fluid causing a transmission to fail. Look on this board for all the posts that start off "FML, my transmission failed, and wouldn't you know it, I even changed the fluid recently". If you choose to take the chance, no problem, rest easy in the knowledge that your transmission probably won't fail due to a fluid change anyway. Just don't expect it to last longer, that is my point.

[sunny5280]

Originally Posted by JCL

Have you ever worked overhauling transmissions? I suspect not. It isn't a non issue to those of us who have, but it may be to you. That's cool.

No I have not. Nor do I work rebuilding engines. That doesn't mean I can't make an informed decision about whether I should change the engine oil. I've spoke with my mechanic about this prior to having the transmission fluid in my X5 changed. He's well aware of this ubran legend and doesn't buy into it. That, combined with a complete lack of supporting data, is enough for me.

No argument. Only issue is, is it relevant? Are X5 transmissions failing due to lubricant quality? Not according to the posting history on this board and others. Sensor failures, actuator failures, programming failures, are all unrelated to fluid quality. They are at the root of many early transmission failures. Changing the fluid won't improve your odds.

They could be. But I'm not arguing pro transmission fluid replacement (though I think it's a good idea). I'm arguing I have seen no evidence to support changing it increases the likelyhood of failure. And so far you've provided no such data either. Just anecdotes stating you've seen transmissions fail after the fluid was changed. It is your theory the transmission failed because of the fluid change but you cannot offer anything other than a theory. What is surprising is you continue to say there's a slight chance it could happen. Of which I agree. However slight does not make a correlation.

Then you should change your transmission fluid. You are the only one who will live with the consequences, so just do it.

Already done.

My reasoning is based on working in a shop. I can't tell you what to do, just that I won't change my own transmission fluid. I do believe in preventative maintenance. I just believe that in the case of the X5 transmission, the risks outweigh the benefits.

That's fine. I'm not here to convince you to change your fluid. You feel there's no benefit. I disagree. Fluids break down. They get dirty. Replacing them is good maintenance, IMO.

However I did ask what the risks are to changing the fluid. So far the only risk I've received is that there's a slight possibility doing so could dislodge some sediment. Which I'm sure there are some examples. Not enough to offset the benefit of changing it...IMO.

I wasn't referring to those cases. I was referring to the multiple cases where a transmission worked fine, up until soon after it had the transmission fluid changed. It happens too often. Technicians in transmission repair shops know about it. You can discount it if you like. It is the reason that those of us who have rebuilt transmissions make judgement calls on whether to change the fluid in this case. I think there is a small chance of a fluid change causing a failure, overall. I think there is even less likelihood of degraded fluid causing a transmission to fail. Look on this board for all the posts that start off "FML, my transmission failed, and wouldn't you know it, I even changed the fluid recently". If you choose to take the chance, no problem, rest easy in the knowledge that your transmission probably won't fail due to a fluid change anyway. Just don't expect it to last longer, that is my point.

But you can't say the transmission failure was due to changing the fluid (unlikely, IMO) or some other issue of which a transmission fluid change was a last ditch effort to avoid a costly transmission rebuild/replacement.

You're also forgetting that a transmission shop isn't going to see all the transmissions where a fluid change was performed and no failure resulted. So your sample is limited almost exclusively to those transmission which failed.

[Mikedd]

Originally Posted by JCL

Have you ever worked overhauling transmissions? I suspect not. It isn't a non issue to those of us who have, but it may be to you. That's cool.



No argument. Only issue is, is it relevant? Are X5 transmissions failing due to lubricant quality? Not according to the posting history on this board and others. Sensor failures, actuator failures, programming failures, are all unrelated to fluid quality. They are at the root of many early transmission failures. Changing the fluid won't improve your odds.



Then you should change your transmission fluid. You are the only one who will live with the consequences, so just do it.



My reasoning is based on working in a shop. I can't tell you what to do, just that I won't change my own transmission fluid. I do believe in preventative maintenance. I just believe that in the case of the X5 transmission, the risks outweigh the benefits.



I wasn't referring to those cases. I was referring to the multiple cases where a transmission worked fine, up until soon after it had the transmission fluid changed. It happens too often. Technicians in transmission repair shops know about it. You can discount it if you like. It is the reason that those of us who have rebuilt transmissions make judgement calls on whether to change the fluid in this case. I think there is a small chance of a fluid change causing a failure, overall. I think there is even less likelihood of degraded fluid causing a transmission to fail. Look on this board for all the posts that start off "FML, my transmission failed, and wouldn't you know it, I even changed the fluid recently". If you choose to take the chance, no problem, rest easy in the knowledge that your transmission probably won't fail due to a fluid change anyway. Just don't expect it to last longer, that is my point.

We did a poll on here on that very subject of failing transmissions after fluid change. Mind you it was far from statistically accurate but I was very surprised to see that no one had reported a failure after fluid change and 10K mles after. I was really surprised and the more I asked the more of "urban legend" it seemed to become. Certainly out of proportion to reality.