Transmission box problem?

I live in Mexico City and have a 2008 CX-9 with 18000km (around 11,000 miles). I recently went to acapulco for the weekend and on my way back (70km from acapulco) without any previous notice we heard a loud noise coming from the engine (like if we hit something). Suddenly the engine light turned on on the dashboard as well as the initials AT. I completely lost power and had to pull to a side. I turned the engine off and then on again. Nothing changed. I put it on drive and it was like I had put it on neutral; did not go forward. The reverse did work.
They towed my CX-9 to Mexico City and has been in the dealership for two weeks now. They dont really know what the exact problem might be. They say it has to do with the transmission (I knew that already of course) and that they are running some diagnostic tests.
Has anyone heard of a similar problem with the CX-9?
Thanks.

First time I heard of any transmission issue with CX9s (partly because most of them are still low mileage). However, with only 11K miles, I would be suspicious that someone put the wrong fluid in the transmission. Did you recall any work done to that? Or, did the dealer mechanic messed it up?

The fluid of the transmission is synthetic. Wrong fluid would cause it to seize up.
It has happened to some early 2007 models in US since some dealer mechanics messed that up with wrong fluid. Some thing happened to lots of MDX in early model years.

The transmission is from Aisin, who also supplies Toyota/Lexus. The reliability/smoothness reputation is widely recognized. Of course, there still may be a few outliers out there. Unlike the previous massive recalls of Honda transmission problem.

I don't know about the warranty there, but hopefully, it is covered.

The only work was in the dealership where I bought it and it was for the 10000 km service. That was 14 months ago and they did not put any transmission fluid in the car.
I forgot to mentioned that when that happened I was using the cruise control. Any ideas?

At least in US, a dealer mechanic is supposed to top off all fluid before delivery to customers. That usually is when the mechanice made a mistake by putting in wrong fluid.

Update

After 3 weeks I got my CX-9 back yesterday. Apparently the problem was the speed sensor which they had to change and reprogram the transmission box.
Hopefully this wont happen again.

So, it is not the transmission itself, correct?