Just joined this forum because my 2008 Taurus X AWD has had some shifting problems. It has a hard time getting into 2nd and super revs before it backs off. Also I've had 3 experiences with the front end feeling like I either hit something or the tire went flat. What happens is the car looses power and sinks down a bit while making a noise that sounds like I hit a pothole or popped a tire. If someone is on the car with me they swear I hit something - but we get out of the car and there isn't anything. NOW my steering is extremely tight but the fluid levels are fine.
When I bought the car I had some front end steering issues as far as making noises when I made turns. They had to lubricate something which was part of a technical buleting and that was it.
I have had no sensations of hitting like you are reporting.
The only slight hitting from the transmision is rare but it occurs when I back off the gas when the engine has reved up thinking that it needs to shift and then I let back off of the gas pedal.
About the revs thing. I noticed on occasion that it does rev a bit unnormally too high before it goes into gear, it could be 2nd since it happens when I pull away from a stop so the car is already moving and it has to shift again. However the revs are not high to worry about but enough to notice that something is funny.
That's all I got on your items, but I would definetilly take it back to the dealer or a shop because there should never be a hit like you would think about looking outside to see if you hit something. Although when I think about it what it sounds like is that the car is about to stall and then it starts up again. The stopping and starting of the engine could be the hitting sound that you are describing with some internal parts hitting each other. I had my car stall twice in about a year and a half of ownership but it was always very quiet at a stop with no hitting.
I have an aquaintance, a mechanic, that has an Edge which has the same 3.5 engine and had the stopping issue right off of the bat when it was brand new. They had to replace the engine because some internal engine parts knocked against each other and the engine required replacement.
Did you by any chance notice any engine knocking sound or vibrations while stopping at the lights, especially if you just drove a bit aggresively. Please let me know because I still have this problem even though they adjusted my engine mounts.
Many thanks and good luck - please let me know how everything is going.