2001 Dodge Intrepid SOME KIND OF PROBLEM

I have a 2001 Dodge Intrepid, 2.7 liter, automatic transmission and 189,000 kilometers. Today when I was backing out of the driveway it went into reverse fine. When I went in drive all the lights on the dash, REVERSE, DRIVE, PARK, were all on. And when I drove my odometer wouldn't work and it wouldn't go into the next gear.I take that back it pops in to frist gear after i let off teh gas but after that it will not go in to the other gears. I know this car has a lot of senors and i trying to find out should i get the sensor replaced or the whole transmission NOW I HAVE TAKEN THE CAR TO AUTO ZONE AND THEY HOOK IT UP TO A COMPUTER AND IT CAME UP WITH SENSOR THIS SENSOR THAT SOME IN THE TRANSMISSION AND SOME IN THE ENGINE. I JUST GOT THE ENGINE FIXED AND I HAVE RESET THE BATTARY. NOW WITH THE COMPUTER GIVING ME THESE CODES AND THERE LIKE 10 OF THEM NOW WOULD THAT MEAN I HAVE TO REPLACE THE TRANSMISSION AND I FOR GOT TO SAY SOMETIME WHEN I DID DRIVE IT IT WILL CUT OFF BY ITSELF AND IT WILL START BACK UP. codes P0700 & P0715
now i have change the input and the output speed sensor and i am having the same problem. now what do i check for now.