2009 Mercury Grand Marquis transmission problems
 

Went out to the car after work one day, got about 100 yards down the driveway and as the car shifted itself from 1st to 2nd gear, it jerked forward extremely hard and stalled. Checked the transmission dipstick to find that it was very low on fluid. I checked the engine bay as well as underneath the car and found no signs of a leak anywhere. I added about a quart of transmission fluid and was able to drive it home with no issues of shifting from 1st to 2nd to 3rd and so on. The only problem I have Is when shifting from park to drive; the car immediately stalls. No problems when going into reverse, just when shifting into drive. I have no lights on the dash, and no noises can be heard. Any ideas as to what this could be?