Transfer case fluid done!

[Quicksilver]

Interesting

After the transfer case fluid has been changed what specifically needs to be updated via computer in my 2005 4.4, and why.

[garrett.fell]

The properties of the new fluid vs the old are different enough to the extent that you need to tell the transfer case to re-learn or rather "forget" how it was manipulating the clutch-packs in the transfer case

Probably not the best description - but close enough.


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[Brads2002]

Hey Garrett,
Hoping you can help...the software is working, seller has been really helpful and quick to respond.

I got all the way to the oil change screen shot you had. When i click on oil change it highlights and brings it down to the lower row. What do i do from there? The right hand green arrow didnt light up so I dont know how to activate. How did you get to that next screen?

It seems to be communicating fine. I was able to activate the clutches in the transfer case.

QuickSilver...this only applies if you have the xdrive transfer case. It readjusts the clutches to compensate for the new fluid. Apparently they self adjust as the fluid ages.

MikeM reccommends changing the fluid twice driving for a short distance inbetween. I guess the second batch comes out pretty ugly. I will post some pictures if i can get this software to work.

[garrett.fell]

Click on the right arrow in the bottom right corner of the screen? I don't recall off the top of my head....


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[Brads2002]

agh, yeah i tried that but for whatever reason its not lit up in green and wont allow me to click. Maybe the seller can help. I will ask...

[JCL]

Originally Posted by Quicksilver

Interesting

After the transfer case fluid has been changed what specifically needs to be updated via computer in my 2005 4.4, and why.

Your x drive X5 (2004 onwards) has clutches in the transfer case that direct power to both front and rear axles. Those clutches are wet clutches, and the actuator presses the multiple clutch plates together. The transfer case expects a certain engagement rate (sort of like how fast you let a manual clutch out, or how slowly). When you change the fluid the wet clutches engage differently as the fluid is different. The transfer case has stored (adaptations) how the clutches react. When you change the fluid you need to tell it to go recalibrate itself, because it doesn't know there is new fluid there. In general terms, it moves the actuator from fully engaged to fully disengaged, and checks the range. Then it measures the % slip and adjusts engagement pressure to get the right % slip. All resetting it after a fluid change does is tell it that the fluid is now different, so just go do that self-calibration again, and use the new stored value, not the old one, for daily operation.

Not doing that would be like changing out some part that you normally adjust from time to time, but not resetting it and just trusting that the old setting would be fine. An example would be valve clearance, when you change camshafts. Someone will say that theirs was fine, no problems. OK, it could be perfect. But it could be too loose or too tight, and the right way to do it is to check valve clearances. Another example would be getting an alignment after changing suspension components. In the case of the x drive transfer case, let it do a self calibration because the downside of it slipping continuously, or being too tight, could be far more costly than the consequences of not changing the fluid.

There is another setting that may need to be reset. It is the one that says the fluid characteristics are now out of the expected range, so change the fluid. After changing the fluid, that one should be reset. But it likely has less to do with how it operates, and more to do with whether the next warning will be relevant or not.

[garrett.fell]

The rest of the menus go like this.....






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[garrett.fell]

Brads - what if you highlight it and click on "test schedule". (Wondering if that's what I did - then run test schedule)



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[Brads2002]

Thanks so much for posting that. I can get all the way to the first screen and click on oil change. It highlights and carries it down to the box below to where your first screen shows transmission. From there i dont know what to do. The green arrow doesnt light up and it doesnt switch to a new screen. I can imagine you would remember it giving you an issue. Either somethings not talking or i dont know what i am doing.
So close!

I do appreciate the screen shots...that will help if i can get past this stage.

[Brads2002]

That was it! Glad to have this off my mind. Thanks so much for the help. Will post pictures of the second drain. The first was pretty dark. This is the last of the fluids. Both diffs were very clean but the tranny and transfer case were filthy.