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Old 11-23-2012, 08:33 AM
F32Fleet F32Fleet is offline
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Location: SE United States
Join Date: Jul 2010
Posts: 1,988
Mein Auto: 435i, 335d sold.
Originally Posted by ard View Post
You specifically said there are analyses that show fluid is good at 70k.

So I am confused why you are linking to a UOA that shows a failed fluid???? Lower viscosity than is required; higher insolubles; higher wear metals. Their averages are based on 30k miles...this UOA is 2x that in length but wear is 2x, 3x, 5x more.... what are you seeing that says 70k is fine



PS I am a bit of a fanatic on ATF- if there is data supporting BMWs position, then lets see it...but I refuse to allow causal assertions go unchallenged.
Look @ links again. There are 2 links @ same mileage(70k). One good one bad.

One thing to keep in mind with UOA's. I have yet to read where BS or any other company state that they have the condemnation figures for any BMW engine or ZF transmission. From my understanding their figures are based off universal averages of samples they receive. Those averages could be lower or higher than what the manufacturer deems acceptable.

In addition due to the low frequency of ATF changes and the even lower frequency of a UOA being delivered technically there are not enough data points to determine a good plan of action however there is more evidence that a 70k change interval is more appropriate than a 30k interval. What is this evidence you say? ZF published a severe service schedule of 48k-70k miles. The 6HP has been used in millions of vehicles (BMW,Jag,Audi,Rover,Bentley,Hyundai) and theses units have not been deemed as weak or have there been statistically significant numbers of failures. The two UOA's show high wear but its a toss up. All of this beats the anecdotal feel good reasoning behind a 30k mile OCI.

On side note I'm doing a pan drop at 50k miles. I don't like the how BMW programmed the transmission to hold 3rd or 4th gear to promote faster warm up on cold starts. It also holds this gear in city driving (trying to sustain engine temps for emissions perhaps?) as well. I just don't like it. I don't mind spending the money to do it and I'll send off a sample to BS so they can add to their data base.

Sent from my MB525 using Bimmer App

Last edited by F32Fleet; 11-23-2012 at 09:00 AM.
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