Weird feeling in the rear ??

I have a 2007 BMW X 3.0 SI and there is something new going on.
When I stop at a stop sign or traffic light, there is a feeling like a weird downshift feeling but its in the rear and I cant explain it really other than what I just said.

Do any of you know what this might be before I venture to get it checked out?

Again its just like a rough feeling like a downshift or something but its odd cause I dont think it is a downshifting that I am feeling. Hope this makes some sort of sense.

does it feel like a jerking motion when downshifting? If so, I used to get that a lot when I first got the car.... it went away once I changed the TC fluid though and so far I no longer feel it.

What it felt like for me was, when you are coming to a stop, if you look at your RPM's you will notice that the car starts to downshift... so let's say the tranny was in 3rd, I would see it go down to 2nd, but then there would be like a small jerking switching to 1st. Like I said, a new TC fluid solved it.

It does it right when you come to a stop like it is probably already downshifted to FIRST and you are rolling to a stop and it feels like the rear end is sitting down or something. I wish I could explain it better.

I had the same feeling in my 2005 Saab X-7 (actually a Trailblazer/Envoy), which I owned before the X3.

Sometimes, it was hardly noticeable but at other times it felt like someone rear-ended the truck.

The problem was/is that the clutches in the transfer case would not release properly. The "Trailvoy" forum had considerable traffic on this issue but no one had any "Quick" fixes. The common consensus was that the full-time all wheel drive system was at fault. Some members went as far as attempting to install a manual switch to disable the automatic four wheel drive selection.

The only thing that seemed to provide some improvement was changing the transfer case fluid.

Weird feeling in the rear.... LOOOOL

Could be the infameous T-case "clunk" we have been dealing with a lot lately here on the forum. If you are over 45000 or so miles I would get it changed regardless. Hard to tell from the explanation you provided but if it is the tcase, many describe this feeling as a "clunk" feeling and/or noise.