If the fluid is lifetime, then why is there a drain plug? Some cars have a change interval for the A T F, but no drain plugs. If BMW didn't want people to change the fluid they could had spec zf to delete the drain plug. After all zf had to provide a bell housing that would mate their trans to the various car manufacturers that uses that trans.

For completing repairs inside the sump. After which the fluid is reinstalled, either the original fluid or new fluid.

We don't know if BMW wanted people to not change the fluid.

We just know that they didn't want to be involved if people did change the fluid, because they didn't develop a service procedure to do so.

Wordplay? Service is a noun and a verb. When you do a service on your transmission, you complete service work. The steps you follow to do that work are called a service procedure.

Sorry, I thought you were familiar with service procedures. It is a pretty common term in shops and service management.

BMW acknowledged that the fluid could be changed, or should be changed. But they left themselves out of that service (procedure) discussion from that point forward.

Nice knot.

Seems you knew what a procedure was a few pages back. :rofl:

Pedantic wordplay indeed

Yes, word play. I've saying service interval. You used the word procedure. Now you're attempting to find fault in what I've said by attempting to attribute your wording to me. I would appreciate it if you would argue what I've written...not what you're attempting to attribute to me. Better yet argue the spirit of the discussion and not the words used to convey it.

Yes, pedantic word play. If you go back and re-read my posts you can see where I've repeatedly used the word(s) service / service interval. Perhaps I may have used the word procedure when I meant service / service interval...big whoop. If this is the best you can do in defense of your position then don't even bother. It's as stupid as someone attempting to argue the incorrect use of the word "your" instead of "you're". But if it's all you got...well, so be it.

WOW this is a HOT topic.....I only read a few pages. No one should single anyone out because they believe they are absolute. That's what sparks ridicules back and forth attaches on fellow BMW enthusiasts.

Now the monkey wrench.......My dealer will not do a trans service on my car. They told me it's for life and will touch it and say it opens up a can or warms with problem. Any Indy will change it for you though.

Can we talk about what oil is the best to use next! or what color X5 is the fastest :D

We are all BMW addicts, some worse then others....be kind to all your fellow brethren.

JCL, I commend your patience, politeness, and rational behavior throughout all this. Thanks for your measured and cautiously factual contributions to this controversial topic. I expect I'm speaking for many other relatively silent readers on this list, but won't be so bold to claim that I do.

Your approach shows that you have a technical background and experience with solving real problems with real consequences.

4 months ago I bought a 2001 3.0i with 169k miles on the 5L40-E/GM5 (A5S 390R) 5-speed auto transmission made by GM. Expecting (turned out I was right) that the ATF was original, I read everything I could about the issue, paying extra close attention to your posts, which seemed the most balanced and rational.

Although having read many first-hand reports out there of AT failure soon after ATF change, seemingly most done by professionals, I decided to do it myself very carefully. I did, with excellent immediate results. Extremely dirty fluid came out, very fine debris covering the pan and magnet. Smoother shifting, all good. 400 miles later, I did it again (another new filter, another 7 qts of Dexron VI).

So here's a data point ...

Upon close inspection (I was in engineering experiment mode throughout this - I had cut open the original filter to inspect it, etc.) I noticed in the pan upon removal a pea-sized greasy glob of stuff. This was entirely unlike anything seen the first time I changed fluid (uniform, fine, microscopic debris). I also saw a tiny shard from a gear tooth - not enough to cause problems, visible only because it was so shiny, but again, unlike anything seen on the first change.

So to me, this supports the theory / legend / wive's tale of new fluid with new additives breaking down old goop and setting it free in the system. Being as cautious as I am, I drove the truck like a granny throughout this period, hoping that if anything broke loose, the light load would give it more of a chance to work its way out safely.

In particular, I thought about the comments JCL made about how broken-loose deposits would get into the valve bodies and ... catastrophic damage. One question I still have about that is why catastrophic and irreversible damage occurs so frequently. I.e., are things really so delicate that a glob of goop in the wrong spot will cause self-destruction before it dissolves? (I guess they must be)

Anyway, I'm now probably 1k miles since that second change. Fluid was still extremely dirty, and I'll probably change again towards the end of the year. Car is running great.

If your E53 is model years 2002 - 2006 point them to the references warratny and service booklet which clearly states the fluid should be changed at 100K mile intervals.

Then it's your opinion BMW is wrong with their 100K mile change interval?