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I just read this thread to refamiliarize myself with it. I stand by what I said previously, but I didn't ever mention the higher detergent content of the new fluid, not sure why. That high detergent level (by design, part of the fluid spec) tends to clean out the old crud, moving it. I think that is part of the reason for problems appearing after fluid changes of transmissions that were working fine prior to the change.
FSETH: Look at the tear down pictures in the threads on this site, and see the number of broken snap rings, and things of that nature. No way an oil change is going to help prevent those types of failure. I wouldn't use the word 'flaky', but I would use the words 'overly complex'. Complexity is the enemy of reliability. With respect to Mr Miller's recommendations, I don't understand how they can be called 'old school' while he is not recommending using an approved fluid. To me, old school is conservative and traditional, and that would include using recommended fluids if one did decide to change it.
ARD: You know that changing transmission fluid regularly (and early) may prevent problems of changing aged fluid (no crud to move, etc). But IMO you should also acknowledge that changing the fluid in that way does not ensure that a transmission will run 20 years (or however long the vehicle will last). Failures we are seeing posted do not appear to be related to fluid breakdown. Your point on understanding cause and effect. So while an early and unscheduled fluid change is intuitively a good thing, it is like buying a lottery ticket; it may pay off, but it probably won't. That goes back to the point in that article I posted earlier in this thread, that transmission failures are not necessarily more likely as the transmission ages. The random nature of the failures we have seen supports that. Also, if you could test transmission fluid, what would you test for? How would you quantify the state of the friction modifiers? And finally, how can you call a lifetime fluid recommendation ridiculous without any data on transmission failures and respective causes?
Cheers
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
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