I'm making this a sticky and merging all new AT threads from the main page into this one (I can not move older threads into this one because it will insert the previous messages above/before this post).
Thanks to AzNMpower32 for this summary:
The problem: A portion of 2007-08 X3s built between 9/2006 and 11/2007 my have possible faulty transmission software programming. This affects X3s equipped with the 6-speed automatic gearbox. The gearbox may fail to respond to throttle inputs, fail to engage a lower gear, or downshift very roughly in normal Drive mode. The problem is not exhibited in manual mode. Cold temperatures may or may not make the shifting quality worse.
The BMW fix There is a software update, this is the latest release as of 10/07
Thanks to AzNMpower32 for this summary:
The problem: A portion of 2007-08 X3s built between 9/2006 and 11/2007 my have possible faulty transmission software programming. This affects X3s equipped with the 6-speed automatic gearbox. The gearbox may fail to respond to throttle inputs, fail to engage a lower gear, or downshift very roughly in normal Drive mode. The problem is not exhibited in manual mode. Cold temperatures may or may not make the shifting quality worse.
The BMW fix There is a software update, this is the latest release as of 10/07
Please post all future complaints and/or attempted resolutions on this thread! Thank you.