2000 mustang GT auto Transmission . Wasn’t moving in Drive or Reverse. So I change the filter and the ATF. Added 6qt of MERCON V. Now the transmission is engaging but is rolling forward in Drive and Neutral and even Reverse the car is launching forward and backs in all gears almost like I press gas but I didn’t. I don’t know if I red to check the shift linkage I did losing the bolt some to remove the pan because the car was stuck on uneven ground when I check the ATF the dip stick was completely dry even tho I added 6qt. yes I did check it on uneven grounds because the car is stuck right there. I just need help I don’t knew if the transmission need another 2qt of ATF or it’s the shift linkage or something else .