My car is reading transmission fault sometimes it will not get out of park and other times it will jump into drive which will leave me third gear. i previously put a re-built alternator
also topped off my transmission fluid. I also took it to a shop, I was told that the transmission was shot. which I know clearly its not, if it was shot I would not been able to drive the car so I need advice on the next move to make when it comes to fixing this problem.