This happened yesterday... I was driving in SD and the car, when going from 4th to 5th gear (I believe), felt like someone hit it from behind it shifted so hard. After that, the yellow gear light with the exclamation point popped up and the car wouldn't leave 3rd gear. I tried adjusting it manually and no change.
Once I pulled over, turned the car off and restarted it, the warning was gone but, even in D, it didn't really seem to shift right.
I did some searching and I found responses ranging from "that's normal" to "I need a new $7000 transmission".
Anyone else have this type of thing happen? This is a 335xi twin turbo with a little over 85k on the odometer. I just picked this up around 2-3 weeks ago, so I'm waiting on the dealer (independent) to call me back. Hope it's not the transmission breaking... that would suck.
Let me also add that I haven't made any mods at all. Yet
