The transmission hit by putting maximum change 2004

Someone can help me with this problem,
the transmission Aut. Of a maximum 2004, 3.5l engine
hit when it is direct (it does not always happen), or also when I directly do not advance well, it lacks strength, the and tried to get manual and melted and melted me marks me 5 speed when starting, I have to turn off the car and turn it on again and then it works well. When I bought it, they told me that the transmission had changed because the previous one was damaged

Good night, you need to run if automatic transmission is fine at the oil level, then check if your motor supports are not so damaged as to see if it is not a cause of false contact.