Transmission problems (i guess)

Hello everybody. I'm experiencing problems with my 2001 Malibu. My transmission, intermittently, has been shifting really hard lately, as I am driving (all gears), and when I put it in Reverse, or Drive from park position. The car just sort of lurches. After that, I recieved a check engine light, went to have it read. I got a "P0716: Input/Turbine Speed Sensor Circuit Range/Performance.

I took it to a dealer (bad mistake i guess) and asked them if they know what is up with this code. They said it could be internal transmission problem, or the PCM. I have trouble believing it is either, cause it doesn't happen all the time, just as times. (usually after driving for a little while). Otherwise it runs really smoothly. Anybody else have this problem? Anybody with good news that it may not be as expensive as i think to fix this? Thanks for all the help in advance!

Thank you. That was a big help, I hope that's all that is wrong with it.
It fits the description perfectly.