Diff fluid changes and transfer case

[diesaroo]

Originally Posted by JCL

I don't have a copy of the TIS, so I can't provide original references. However, the following are all posted on this site. Credit given to texmin, ripp222, and skeetjunkie:

Posted in response to where to find the TIS reference:



texmin wrote up a DIY, found the reference in the TIS, and reported that he never did do it. Not sure if he has done so since.

Posted in reference to how to cleare the VTG fault:



That refers specifically to the VTG fault when the fluid no longer meets spec, not the adaptation values that are to be reset whether or not the fault has been raised.

Posted in a discussion on why it matters:



It is that last information from Mike Miller that gives me pause to think. It makes sense that the adaptations are important for future transfer case clutch plate life, not just for a warning as to when the fluid is due to be replaced. Many have posted that they changed the fluid without resetting the adaptations, and it still drove fine. That is certainly possible, but IMO they won't be able to judge their success until they see if the transfer case lasts as long as expected without the adaptations being reset. Incorrect clutch pressures will lead to shortened clutch plate life if too low, and potentially to actuator motor failures if too high.

Jeff, I totally agree with your logic. My TC is a little newer than the ones you are referencing (ATC 700). I'm looking at 27 00 Repleneshing / Changing Transfer Case Oil (ATC 700). Nowhere in the document does it state that the BMW repair diagnostics should be consulted. It does say so in a different repair procedure regarding the TC replacement or the replacement of the TC servomotor that BMW Repair Diagnostics should be run.

I guess I'm still wondering if the newer TC software has been changed from the prevoius models or do I simply not have enough information?..