I've just had mine changed at 95k. Indy tells me it came out really clean. One of the cleanest trans fluid he has ever seen, so there is a possibility it's been done before, but I don't think it has been. Certainly no record. Mine is 2004 4.4. Interesting to note that when I got it a year ago, I also drove my friends 4.8is, and I felt his shifted down the gears so much quicker than mine and at 30-40mph it would almost always be just over 1k revs. Mine never did that. I always felt there was something wrong but loads of people told me that it was normal, and just due to the tuning and greater BHP of the 4.8. However, when I got the fluid changed a few weeks ago, it completely changed the transmission and it started changing down way quicker. It seems the old fluid was a bit low (perhaps) and the box was holding onto the gears for a bit longer.

It's also worth noting that I had an Audi A6 with a CVT box prior to owning the BMW and those boxes are horribly, horribly unreliable. Mine had only one owner before me and he changed his fluid at 50k, then again at 100k, then again at 150k, despite Audi saying it didn't need to be changed. I took over this car at 155k and took it to just shy of 200,000 miles and had zero problems with the gearbox. It was as smooth as silk and the only time I ever had an issue, it turned out to be a turbo needing cleaning and not the box.

So I am a definite fan of changing the fluid regularly, despite what BMW (and the internet!) tells you. Remember that BMW don't care about you after 100k. You are dead to them unless you take your car in for massive expensive repairs. That's why, in my opinion, they tell you the fluid is lifetime, to get people with older cars to pay the £££££ to have their boxes replaced, rather than a relatively cheap service job.

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BMW X5 4.4 2004