I know this is an old thread but I just saw it.

My 05 4.4 had been doing this since I bought it as a cert pre owned in 07. As I described it to BMW it felt like it was skipping 1st gear (auto trans) and going straight to 2nd with a clunk. I too got the stares from pedestrians and the "what the hells" from passengers.

After complaining several times to BMW (like 10) they "reset the computer" "rebooted the computer" "upgraded software" (these are all things I was told). I was also told that "this is just something all X5's do, it's a glitch. Ya like I was going to swallow that. I may be a woman but I'm not stupid.

I finally threatened to take the problem to BMW corporate. Not until then was I offered to have a new transmission put in. Problem solved!