Placed in Drive car felt like it was going to lurch/jump forward and made a loud noise.  check engine light is now on.  Engine was cold.  Checked all other gears they felt fine and was smooth.  It only has happend in Drive.  Checked gears after I got home from work.  ALL the gears felt fine and smooth.  Automatic transmission.

What would cause this?  Should I be afraid to drive to work tonight?