Frank:

A thoughtful post, lots of details. A couple of comments:

• Agree that the fluid is very expensive. Problem is, we don't know exactly what they changed, if anything. I suspect they have some of their own additives, but there isn't a lot of detail available
• Not sure how you get soot in a transmission, but agree that you could have black sludge. No combustion going on in there, to my knowledge. Probably semantics.
• Agree that transmission failures happen irrespective of fluid changes. I haven't seen a good analysis that shows the correlation of fluid changes and failures. I know that BMW transmissions don't last as long as many would like, certainly not equal to engine life as an example. I think the fluid is transmission lifetime, not vehicle lifetime. I just don't think that changing the fluid is shown to increase transmission life. While the idea of fresh fluid is appealing, it comes at the cost of disturbing what is there, ie it isn't a free benefit IMO. My sense is that the transmission is going to fail at some point, and driving habits, as well as luck of the draw, has as much to do with it as fluid changes.
• The No Reverse site is interesting. A bit of a rant, but interesting.
• I think that the change to included maintenance is not as related to the move to longer term fluid change intervals as some put forth. Fluids are lasting longer whether or not maintenance is included. You don't get transmission fluid change included in your Canadian X5, so it is more of a US theory. Also, BMW continues to pay the warranty costs. Believing that this maintenance practice leads to a failure just after the warranty expires seems too much like a conspiracy plot to me.
• I do believe strongly in changing fluids. I just don't include automatic transmission fluids in that list. Engine oil, coolant, and brake fluid are at the top of my list. If I owned a vehicle long enough, I would change the power steering fluid. I don't see the need to change the fluid in all compartments, as the contamination paths are different. If I went offroading, I would change diff fluids, for example. I don't think that engine oil change intervals relate to transmission fluid change intervals, due to the lack of combustion byproducts, the sealed nature of the system, etc.
• Not a tender subject at all, in fact it is an interesting one.

Best of luck in your repairs.

Jeff

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue