I have read the same thing about the alternator...but somewhere in this thread it also mentions the possiblity of a bad Park-Nuetral Switch...it was a recall item on the 2001 4.4...I did a little research and THAT is what mine sounds like...

Symptoms are...When I stop the SAV and throw it in Park the Transmission Failsafe Mode often comes on...it also comes on frequently upon start up but IF I turn the SAV off and restart 9 chances out of ten it does not return and the car drives FLAWLESSLY...I am hopeful this is MY problem and have to get five minutes to call the dealer to see if the recall has been preformed on this particular SAV since I bought it used just a few months ago...

Here is the link...

http://www.automotive.com/2001/49/bm...lls/63338.html


You may need to copy and paste as I don't think I inserted it right! If it does not work ...just do a search for "BMW X5 Recalls Park Nuetral"

I don't know if this will help anyone but...I am going to check it out!!!