2010 Ford Edge drivetrain & axles problems

I was attempting to park on a steep incline in san francisco on a rainy day, because I was aware that my vehicle tends to roll backwards upon releasing the brake (even when in drive), I decided to not park in that spot and was very careful to shift into drive and gun the gas so the car would move forward and not roll back into anything behind me. I had successfully used this technique before, but this time gunning the gas still resulted in my rolling backwards and caused a collision.

Dec 17,2016 a severe jerking while driving on a village main st. Wrench light came on. I stopped car, got car manual, saw that it was power train problem. I began googling and will see my mechanic on monday. The first time this happened about 3wks ago I lost driving power and drove my wife to work on idle power. When I got home I shut off car and started again and it worked ok (except for mild jerking) until now (3wks later).