2002 Ford Explorer Won't shift into Park

I had the transmission re-build in August 2008. Six months after repair, transmission won't sometimes engage when put in reverse, from "D" to "R" after I stop. Took it back to the repair shop and was told nothing wrong with it-they usually tried couple of times and it seems to work fine. They also hooked it to the code reader, and there was no given code - or at least that what I was told. Now my one year warranty expeired. Yeasterday, and after warming the car for about 3 minutes, I shift into drive "D", it dies out. Now, I could not shift it into "P" or even start the car. I can shift it in any gear except "P" and it won't start when in neutral "N". I pushed it back and forth few times, still won't shift into "P". Worse, It seems that the transmission does not engage at all in any gear. Sitting on almost flat surface, it free moves in any gear when pushed. Thank you for your help.