Chrysler Repair: PT Cruiser speedometer/trans problem, torque converter, speed sensor

Question
The speedometer on my 02 PT cruiser stopped working. When it stopped the cruise was on and the car sputtered then revvd up again.  A few times since the speedometer stopped the car has acted funny like it could not switch gears or gain power.  My father changed the speed sensor which did not correct the problem.  He also tried to reset the computer by disconnecting the battery. No luck.  What else could be wrong?

Answer
Hi Ellen,
Are you sure that he changed the 'output speed sensor' and not the input speed sensor? They look the same but one is at the far end of the transmisssion and the other one is near the bell housing where the torque converter is located. I would surely suspect the output sensor given that history, so that is why I ask. Are there any fault codes stored in the powertrain computer memory? Turn the ignition key 'on-off-on-off-on and leave on', doing that in 5 seconds or less elapsed time. Then watch the odometer window to see if it changes to show 4-digit codes preceeded by a P.
Roland