I have to say this is pretty surprising info to me that you won't be changing yours at all. I thought that if you change it frequently enough (say every 50,000 miles) then you will avoid the possible 'disaster' that people describe in going from super dirty to super clean fluid.
It seems to me that like all lubricants, ATF breaks down significantly over time and should be changed. Even ZF recommends changing the fluid and considers extended interval to be 100,000 km / 62,000 miles. Mike Miller in his "old school BMW maintenance schedule" also recommends 60,000 mile intervals (he does btw acknowledge the mysterious breakdown issue with high mileage previously unmaintained transmissions; though honestly I don't see how, at least in theory, this issue shouldn't apply to any fluid changes whether it's engine oil, transfer case fluid, power steering fluid, coolant, etc.) It is widely known that BMW now considers lifetime fill as 100,000 miles, and that is now becoming their recommended change interval. So given all the above I would think a transmission would be less likely to crap out due to stirring up gunk at 60,000 miles versus 100,000 miles.
As a reference just look at the fluids in this link as changed at 91,000 miles and 133,000 miles.
Transmission Fluid change on 5HP24 (A5S440Z) x2:
Quote:
Originally Posted by Weasel
Couldn't have said it better myself. Automatic transmissions will fail inevitably just by nature... clutch packs will wear no matter how new the fluid stays. What seems that it would make the most difference is the driving profile as it would be more directly related to clutch wear.
And on a side note, when the clutch discs do wear the clutch material gets suspended in the fluid which thickens the fluid and adds some hydrolic pressure. My last job before BMW was at a trans shop (R&I guy). You'd be amazed of the number or failed transmissions that came in shortly after doing a fluid change simply because the viscosity was lowered, the lubricity was higher, and the clutches just started slipping bad to the point of no return.
I can tell you that on my own personal vehicle, I will not be changing the fluid.
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