Quote:
Originally Posted by desertfox73
Quote:
Originally Posted by DgjoX6M2016
Quote:
Originally Posted by desertfox73
Quote:
Originally Posted by Sophisticated Redneck
The electromagnetic actuator used to engage the clutch packs in transfer case used in the F85's ATC45L is EXTREMELY sensitive to wear. What happens is over time the clutch packs wear/fluid degradation cause it to become out of calibration. This manifest itself in set torque point request failure codes (these are unique codes and will not trigger a check engine light and only show up a scanner that can read BMW codes) the computer is requesting a certain value from the transfer case and when it doesn't receive it, resets the motor over and over in an endless cycle...feels like a trailer tugging or engine miss.
Most of the transfer cases can be fixed simply by changing the transfer case oil and loading up ISTA to perform the transfer case recalibration procedure. Recommend you do this yourself or take to good Indy shop to have it done (I would not trust your SA, they would rather bill you for 9k then 300 dollars...)
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Thanks - very helpful. If BMW doesn't perform the work under warranty then I am planning on having my other shop do it (they would always be cheaper for non-warranty work). I've shared your post with them, appreciate it!
I guess I also wonder why I don't hear of transfer case failures left and right on these boards. Tons of guys run winter setups (or even summer tire setups) that aren't the same size as what comes from the factory. |
I posted my xfer case failure a while back. Exact same symptom as yours. Thought it was a misfire. Happened around 36k miles. Cause was fluid loss, or so they said. Replaced under warranty. Haven't seen many others so they seem fairly tough. Perhaps time will tell.
I have a Dinan Stage 1.
Personally, I am always reticent about adding too much more power as driveline's ability to handle always concerns me. For example, the transmission has certain torque handling limits. 750nm for our models, which is 553lb/ft. I suspect xfer case has similar design limits. Do t know what they are, however.
Tires different size doesn't seem like a valid reason to me unless different diameters front to back, which I don't think is the case with yours.
Are my BMW winter wheel setups the exact same diameter of the stock summer setup?
Best of luck. |
Not sure about your winter set up - but the stock measurements on my original post may help you figure that out. In any case, I'd be cautious that bmw could try to use the "non-OEM" tire excuse if your diameters aren't the same as what rolled off the showroom floor
Quick note: my car has 9400 miles.
No way a transfer case should fail that fast. I don't drive the car hard at all, still have the original tires i put on it (over a year ago). |
My winter setup are BMW OEM. My point being, are OEM winters the exact same as the OEM summers? If they aren't, it suggests the logic behind the dealership answer you received is flawed.