Transmission

[sunny5280]

Originally Posted by JCL

Then, I expect that during teardown a cause of failure will be found. If that failure relates to a hydraulic circuit that has debris in it, I think a reasonable hypothesis will be that the powerful detergents in the new transmission fluid acted as they are designed to do, and cleaned out the sediments, where they lodged in the small passages of the valve body. Cleaning out the valve body now may in fact restore the functioning of the transmission.

I don't think the example is meaningless, but for a reasonable conclusion to be drawn, I would expect something along the lines of the above. Is this the statistical proof based on a sample of 100,000 that you asked for? No, but it is how trained technicians work, and it is the best we have.

The example is meaningless until the type of analysis you've described above has been performed. Until such time it is meaningless.

[HPIA4v2]

Don't we need to look at this:
http://www.xoutpost.com/bmw-sav-foru...igh-miles.html

Not much data but it's something.
The interesting part was some people didn't even drop the pan (changed filter), just flushed the fluid, if the new trans fluid will "clean" and "dislodged" crud etc, we'll see failure even more on these seven people cases. NO?

I am not arguing with anyone, but as a meber of this board I think we all need to point what works and what not. I am not advising people to flush, and if that's the "stupid" thing do to so be known on this board so others don't follow. I don't get paid by Esso or filter OEM company

[sunny5280]

Originally Posted by HPIA4v2

Don't we need to look at this:
http://www.xoutpost.com/bmw-sav-foru...igh-miles.html

Not much data but it's something.

Apparently I wasn't the first to use the characterization of "Urban Legend".

[JCL]

Originally Posted by sunny5280

Apparently I wasn't the first to use the characterization of "Urban Legend".

Great catch!

I suspect my Google searches are customized by Google based on my web search history.

In 733,000 posts here by 55,000 members, there are two of you who have referred to it as an urban legend. You weren't the first, just the most insistent

[Mikedd]

I have put on a fair number of miles since I did that very un scientific poll and I am still good transmission wise as well. I think we should resurrect the poll to get even more data to perhaps dispel the "the urban legend" of transmission fluids. Ha

[wallyx5]

Originally Posted by JCL

Great catch!

I suspect my Google searches are customized by Google based on my web search history.

In 733,000 posts here by 55,000 members, there are two of you who have referred to it as an urban legend. You weren't the first, just the most insistent

Hey JCL,

Wasn't it a nice day in Vancouver. I spent the day traveling around Delta, Richmond, Aldergrove and finishing up in Abbotsford. I love this time of the year. Vancouver summer nights are the best. Thanks for all your help on these threads.

[JCL]

Originally Posted by HPIA4v2

Don't we need to look at this:
http://www.xoutpost.com/bmw-sav-foru...igh-miles.html

Not much data but it's something.
The interesting part was some people didn't even drop the pan (changed filter), just flushed the fluid, if the new trans fluid will "clean" and "dislodge" crud etc, we'll see failure even more on these seven people cases. No?

I am not arguing with anyone, but as a member of this board I think we all need to point what works and what not. I am not advising people to flush, and if that's the "stupid" thing to do so be known on this board so others don't follow. I don't get paid by Esso or filter OEM company

Good question. If owners are going to change the fluid, then IMO it is imperative that they change the filter at the same time. It also isn't a bad idea to go back in a few days later and change the filter again, because it will be after the new fluid is in and has a chance to clean out the internals that one is more likely to get complications.
It really isn't a flush (which uses a special machine, similar to kidney dialysis), but rather a fluid change. Flush is a bit of a misnomer, again IMO.
I don't think that anyone is stupid because they decide to change their fluid. If I had shift problems, it is something I would be likely to do. On the other hand, if I didn't have any shifting problems, I would be unlikely to touch it. I don't think changing the fluid in an otherwise good transmission will be likely to cause a failure, but I definitely think it increases the odds of such a failure, based on my own experience.

My real issue is simply that some people change their fluid for motherhood reasons, because they don't believe the fluid can last as long as the transmission, and those are usually the people who are most surprised if they have a problem afterwards. I think people should make informed choices, that's it. No stupidity is involved in any informed and balanced decision, IMO. I respect individuals' decisions, I just think they in turn should respect other's decisions which may not be the same as their own.

[JCL]

Originally Posted by wallyx5

Hey JCL,

Wasn't it a nice day in Vancouver. I spent the day traveling around Delta, Richmond, Aldergrove and finishing up in Abbotsford. I love this time of the year. Vancouver summer nights are the best. Thanks for all your help on these threads.

It was a great day! Glad you make it up this way. We are headed out tomorrow morning early from downtown, to UBC, Richmond, Steveston, then New West, Coquitlam, Burnaby, and back home, all on the road bikes. Excellent time of year now that the rain has finally let up.

Jeff

[JCL]

Originally Posted by Mikedd

I have put on a fair number of miles since I did that very un scientific poll and I am still good transmission wise as well. I think we should resurrect the poll to get even more data to perhaps dispel the "the urban legend" of transmission fluids. Ha

Save the effort on the poll, it is impossible to get real data. I figure I have stirred the pot enough here today, now you come along to do the same thing...

[X5Sport]

This may, or may not, add to the debate but I have just had my transmission rebuilt after the torque converter failed (lock up sprag clutch sheared) and caused catastophic damage due to debris in the oil damaging various clutches downstream and ruining the oil pump to the extent that metal shavings from the pump wrecked the gearset for 1st to 3rd too. The rebuild shop is a ZF specialist and they want the car back after 6months/6,000 miles to do a complete fluid and filter change. The original failure occurred at 42k miles.

More worryingly - and I pass on on for that reason - was his comment that they are now seeing so may of the 6-speed auto failures (not just in BMWs) they now keep the spares on site whereas they used to special order them. Most of the failures are actually being caused by electronics or electrically controlled hydraulic devices breaking rersulting in downstream failures when vavles operate incorrectly or fail to operate at all - and not fluid related.