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Old 01-18-2013, 08:47 AM
ard ard is offline
Resident Curmudgeon
Location: Sierra foothills
 
Join Date: Jul 2009
Posts: 10,145
Mein Auto: '12 X5 35d/E39M5/996TTX50
Quote:
Originally Posted by smyles View Post
ATF replacement involves changing the transmission filter and altogether, if done right, is $$$, probably 500 or more. One thing to keep in mind, there's no established correlation b/w fluid change and gearbox longevity: live examples of 250+ K miles on original fluid coexist with broken ones where fluid was changed some way - and no one can say for sure (but obviously can speculate) whether it broke due to or despite the change. Also, often the issues are related to mechatronic parts (not fluid related), and you end up dropping the pan and changing some of the fluid anyway.
The whole "there is no data" argument reminds me of the cigarette companies defenses for all those years.... "no data suggesting that cigarettes caused YOUR cancer"

I've read a few people talk about "Oh the fluid doesnt fail, it is some other part" (Hi JCL ) but the fact is that the correlation between fluid degradation, transmnission wear and fouling, and ultimate failures is well known IN GENERAL. But perhaps BMW has engineered aomething that has been impossible for the last 40 years....

So, to be clear: NO TRANSMISSION EVER FAILS DUE TO FLUID FAILURE.

Clear?

The primary failure is part wear and sludge build-ip leading to improper actuation with a resulting range of symptoms.

IMO

A


PS OP- the BMW dealer will almost surely talk you out of a fluid change. Find a good transmission shop with experience in these trannies. My 2 cents
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