2004 Sable DOHC 24V Transmission does not engage gear
 

I have a 2004 Mercury Sable, DOHC. Right after descending from a bridge, the car lost engagement with the gear to drive the car. It simply coasted to a stop. I tried all the gears but none of the gears was engaged to move the car, the rpms simply went up. There was no check engine light and no OBDII codes came up. The engine restarted ok, even 12 hours later on same battery but still no gears engaged.

Please what could be wrong with the car?