I fail to see why this remains an issue. The claim was changing the fluid would lead to transmission failure. However no supporting data has been provided. And no, it's not insulting to call it a wives tale. Again: I clearly have no doubt there are examples of transmission failures after the fluid has been changed. However unless there was an RCA performed on the failed transmission we cannot conclude the fluid change was the cause of the failure. To believe otherwise would be to believe BMW is recommending a service which leads to transmission failure. Do you believe they're doing so?

The BMW owner's manual for the first generation model I had, a 2003, clearly states that it is lifetime fluid. That manual is posted on this site under Online References, as a PDF. In the US Owner's Service Guide that sunny linked, it is stated that the fluid has a lifetime of 100,000 miles, or words to that effect. Conflicting information, and not very helpful.

I think BMW planned for it to be lifetime, and acknowledged that it has a life of 100,000 miles (without getting into severe service conditions, and so on). It isn't possible to draw more conclusions from the owner's documents provided, IMO, due to the lack of detail provided. If one is suspicious, one could say that they figured the transmission would last 100,000 miles, but that isn't directly supported by anything.

Now look at the BMW technical workshop service manuals. They don't just procedures on what to do, what not to do, and what the risks are related to the procedure. They are also an indicator of what BMW trained their dealers to do. They list every procedure for working on these vehicles, including some that are very basic and simple. When you look up the automatic transmission, under Maintenance, General Data and Information, there is only an item about the alignment dowels. Under Maintenance, there are procedures for changing practically every fluid on the vehicle. Differentials, transfer case, manual transmission, engine oil, brake fluid, brake fluid, etc. 65 detailed procedures. Including compartments that have designated lifetime fluids, like the diffs. But no procedure for changing automatic transmission fluid.

Under Repair Instructions, Automatic Transmission, there are procedures relating to the topping up the fluid level, safely handling transmission fluid, re and re of the transmission, and so on. But no drain and fill instructions. There is a sump re and re instruction (clean, replace sealing ring, follow torque specs, no mention of filter, use correct fluid). When replacing a transmission, it states not to fill the new one, as it comes pre filled as a reman. Interesting.

Under Technical Data, Automatic Transmission, it only lists capacities.

Incidentally, if we want to look into "did anything change?" as to service recommendations, all of the updated service recommendations are itemized in the technical manual. So we know if BMW changed their mind based on new data or test results, for example. No matter what some may say. The version I am looking at is dated 08/02/2013, so something may have changed further since then. As examples, the air filter change interval changed for certain models, the brake disk life recommendation changed for certain models, and so on. Nothing about transmission fluid recommendations changing.

In the absence of any procedure for changing the fluid, to claim that BMW see this as a safe procedure is nonsense. They may do so, but they don't recommend changing it. They suggest the fluid has a design life, and some see that as an endorsement of their own position that it is therefore safe, but it appears those people aren't familiar with BMW service procedures.

So this is exactly where we have been for several years now. No new info. BMW claimed a lifetime fluid, and acknowledged that fluid has a design life. They remained silent on "what to do". They don't appear to have developed drain/fill procedures or evaluated the risks of doing so, and they appear to have trained their dealers to do very little with automatic transmissions, to the extent of shipping reman exchange transmissions prefilled, which leaves the dealer out of that filling process. They insist that the correct fluid be used (in many spots in the manuals) but they don't talk about the filter, since they don't expect it to be touched. No wonder dealers don't want to change the fluid. They would be on their own, so to speak.

If you want to change it, I would follow the ZF instructions. Correct fluid, new filter, careful attention to fill level procedure. Or leave it alone. If it works fine, judge whether there is any benefit to changing the fluid. Make that judgement knowing that it isn't about the lubrication issue, but rather the other more critical properties of the fluid. If it has shifting problems, changing the fluid is always cheaper than a new transmission, but may or may not make any difference.

Jeff

The fact remains you have provided no data to support a causation between transmission fluid changes and transmission failures. None. Zero. Nada. Zip. Just anecdotes. Until you provide something other than anecdotes it will remain a wives tale. Especially when it goes against BMW's stated service interval from 2002. Why you continue to argue there's a causation is puzzling.

That is my issue with sunny. He doesn't appear to understand that it is insulting. Maybe he does, and wants to be insulting.

Of course people have changed fluid in a vehicle exhibiting transmission shifting problems and not seen improvement. Irrelevant. Discount those samples. People have also changed fluid incorrectly, or used the wrong fluid, and seen problems. Irrelevant. Discount those samples. The examples I am referring to are when the fluid was changed properly, with the correct fluid, at higher mileage, and a subsequent problem arose. If a failure analysis was then done, and debris was found in the valve body, then it is reasonable to conclude that the fluid change contributed. If the problem is caught right then, and the valve body removed and cleaned, it can be all good again (examples posted here). If the transmission is driven in a slipping mode, to the point of failure, then it is toast (been there).

If you have been personally involved in the above, and sunny calls it an old wive's tale, ie untrue, then to me he is calling the poster incompetent or a liar.

This usually turns into armchair experts debating what BMW meant in non-technical documents like owner's manuals, and trying to make their case. It is usually possible to tie those armchair experts into knots, although it would be better if they knew when it had happened.

But they don't recommend a procedure. Details posted above. They list a fluid life (100,000) and the word lifetime, in two separate documents.

From the technical service manuals, they don't have a procedure. Why do you persist in believing they do?

I have never claimed so. Some might have.

I claimed that it could lead to transmission failure, not that it would. The difference is that if it was claimed it would always happen, one anecdote of it not happening would disprove it.

I called it a small chance, but a likelihood nonetheless. Please don't misquote to try and make your case.

The question isn't about whether BMW recommends a change procedure. The question is whether changing the fluid leads to subsequent transmission failure. Again you have provided no proof to show causation. Just anecdotes. If you have some data let's see it. Otherwise it remains a wives tale.

You just spent innumerable posts trying to prove they recommend a procedure.

Your entire basis for claiming that there is no potential of damage after a high mileage fluid change is that BMW wouldn't recommend a procedure that has a potential for causing damage.

Wait for it....


That is some knot you tied yourself in.

Learn the difference between the words "service" and "procedure". I have used the former...you came up with the latter. Regardless BMW clearly recommends changing it. END OF STORY. Your pedantic wordplay not withstanding.

Likewise would you stop with the "no potential to cause damage" strawman? I've never said nor do I maintain such is the case. I thought I had made myself clear about this yesterday in post # 111.

Now will you please stop with the dishonesty?