Check Engine Light

I have a 01 Aurora with 122,000 miles and the check engine light comes on and then goes off. I've taken it to Auto Zone and they said a 0717 code came up. It read...The PCM has determined that there is no imput voltage signal from the turbine speed sensor. They didn't know what it was, or how to fix it. Can anybody help me?

This is a trans code for the turbine in the torque convertor, somewhat difficult diagnosis, you will need a diagnostic trouble tree here, alldata.com is one or a factory shop manual.

I have noticed it shifting a little hard at times. I assume if its in the torque converter the transmission has to come out, which is going to cost big money.

Possibly the worst code you can have - Sorry - Hopefully you get away cheaper (and it is entirely possible) but check here for more information
http://www.aurorah.proboards47.com/index.cgi?action=display&board=1stgen&thread=1139437014&page=1

Ouch! I don't like the sound of this.