Yes I agree, the Germans have always been ahead of the curve, deploying the latest and greatest technology, sometimes over-engineering a feature. If you ever get a chance to see the front cup holders on an E60, you will know what I mean.
I don't know exactly about JATCO, so do your own research on this specific tranny, but the ZF tranny on recent bimmers also used to be filled for life. Hell, my tranny pan even has a yellow sticker on it , specifying that the ATF is for life. But lately ZF has retracted from that statement, and recommend a flush every 100,000km. If you read on bimmerfest and other forums, you will find most Indys have always recommended this practice.
Regarding my tranny oil mix up, no surprisingly there is no sensor that reports oil and water mix up (although there is one if oil gets below a specific level). I have a strange habit of checking my engine oil and coolant level every week either on Friday or Saturday. This particular week, I happened to recheck the coolant level on a Sunday or Monday as well for some odd reason, so i found that there was a coffee shake brewing in my coolant expansion tank. Then I started investigating as well. I may have driven 100-150 kms with mixed oil and water at that point, but drove about 25 kms or so to take it to the mechanic's workshop, once I found it out.
I initially went to a desi ustaad mechanic on way to my work, who suggested that I drain and flush coolant system and tranny. He suggested to fill the tranny with cheaper Ford ATF and run the car for like 20 kms, so as to flush the tranny and drain this oil, hoping to drain any water and sludge build up as well. Which he did, although I was against this idea of using cheaper Ford oil. The Ford ATF oil was around SR. 15 / liter and ZF spec ATF oil is about SR. 60 / liter and one would need around 6 liters for drain and fill or 9 liter for complete rebuild, as around 3 liters of ATF is contained within the mechantronic sleeves etc.
Anyway, I had done this stupid mistake, and could have lost the tranny, but luckily within driving 20-30 kms, the tranny disks started stuck and the iDrive gave an error and the transmission would not engage any more. The car was stuck in Neutral essentially. I spoke to my real mechanic, and gave him the time to pull out the tranny. I took some pictures of the clutches, and they had a lot of wear and tear (the car had done 180,000km on them), so I decided to completely rebuilt it. Now it is good for another 100,000 km until an oil change would be required. One thing for sure that the tranny feels very light and powerful once the oil is flushed.
The water in the transmission is a very bad thing, as there are some "fiber" plates in the clutches in ZF transmissions, which can withstand ATF oil but not water. If they come in touch with water, the situation becomes grave suddenly. These require changing at that stage. That is the only recommended solution. If the water does not seep too much in the system, it can be salvaged with a quick tranny oil flush. May 2-3 flushes to be safe.
I just had to go the whole 10 yards. But in the end, I saved myself from having to replace the transmission, so it was all good fun... lol I hope you don't have to face similar situation. By the way, if you ever need any major work I would highly recommend Jano BMW Workshop in Dubai. This is one Indy, who has more cars in his workshop than AGMC. :P:D I took my car there last year when I was in Dubai for a quick service. He is highly recommended, and even takes some tuning and supercharging projects!! Here is his location.