Blown Transmission?

[eeee36m3]

Hi. Long time lurker, first time post.

2002 BMW X5 4.4L auto 187K miles.

As I was rounding my last corner before my driveway, I heard a "ping" and then "whiiiiiiiz" and there was no more power being delivered to the wheels. The ping may have been something snapping, and the whiz sounded like the a shaft free spinning against something. I tried putting into Reverse, Drive, power cycled the vehicle, Drive, Reverse... nothing. No power delivered to the wheels.

Luckily I coasted into my driveway, and got about half way up before I ran out of momentum.

Even with the Gear selector in Park, the X5 would roll backwards down my driveway.

I haven't had a chance to crawl under there yet. From realoem, it looks like maybe the power is not being delivered from the transmission to the transfer case, because I don't have power to either the front nor the rear wheels. Or, could it be the transmission itself.

No dash lights, no trans failsafe warnings.... just nothing.

Any insight appreciated. Thanks.