Originally Posted by CoasterDan
Were you in sport mode at the time? The transmission was giving you engine braking by going into a lower gear (or two). Just hit the + button, if you have that, or shift into Drive to upshift.
No, I've never used sport mode. (to be honest, I'm not quite sure how or why or when to use it.)
It was in drive every time, foot off the gas pedal coasting down the grade.