Transmission trouble with a 2004 Dodge Neon?

[Brad]

I have a 2004 Dodge Neon that has been having transmission problems. The speedometer has been going crazy and it has been shifting hard or sometimes not shifting. I changed the speed control sensors today ( input and output), then everything went to hell. The car barely made it around the block so I put the old ones back on and the same, the car is doing worse than what it was doing before