Just beacuse there are people with over 100k miles on a tranny it is NOT proof that ATF service isn't a good idea.

(Indeed, my grandfather smoked for 50 years and was hit by a bus, therefore cigarette smoking is safe.)

The numbers of people drviing 100-150k mile BMWs is rather small, and therefore collecting coherent data from a sample like the internet is pointless. Indeed, the sum total of data we receive on trannies is "needs a rebuilt" or "I traded it in". We will not get details on failure modes.

Your comment about "fluid" being an independent component (ie fluid life longer than MTBF) is a bit off-the fluid is a lubricant for the mechanical assembly... you cannot consider it independently... Here is a analogy: why bother with changing motor oil? Afterall, we rarely read posts of people with 'failed oil', and the odds are that something else in the motor will fail before the motor oil fails...

There is no risk with doing a BMW recommended fluid service. You compare it to surgery- I compare it to a haircut.



Adam

PS thx for the pdf of the sensor.