"D" mode behaves like neutral when engine is turned off

[Zactn]

I have a 2016 CX 9 and had an unexpected thing happen to me today. I parked the car at work (at a very small incline) and turned the engine off by pressing the Start/Stop button. I had forgotten to change the shifter to "Park" since I was preoccupied with something. When I took my foot off the brake, the car began to roll back like it was in neutral. Is this expected? I would have expected that with the engine off and the transmission in "Drive", it would behave just like "Park". Thoughts from others?

 

[mazdadude]

Without fluid being pumped into the torque convertor, there is no coupling between eng/trans.

That's why we have to have a PARK, and also why you cannot push start an automatic.

 

[Odrapnew]

Just what mazdadude said, completely normal.