2002 Chevy Cavalier - Check engine light - Error Code P0742

After I drive for an hour,the check engine light comes on. Then after a few days the light goes away.
I think the error code means that the TCC is stuck. I went to a transmission mechanic, he said he can check the solinoids. If not, it it could be a $2K rebuild

What is the possibility that it is a Solenoid problem?

According to Service Bulletin #02-07-30-013E, May 2005, if you have the 4T65-E transmission, the problem is caused by machining chips or debris in:

All year models: Pressure regulator valve ( Bore 1), stuck
Torque signal valve (Bore 4) stuck

2001-2002 : A plugged orfice on the case side of the spacer plate.

The Bulletin reccomends cleaning or replacing the valve body.

When is the last time you had a transmission service on the vehicle ?

Thank you very much.

I have not had any transmission service yet.

If I empty the transmission fluid is emptied on the pan and have lot of visible chips/debris or bad color, does it imply that the chances are that I may have a big transmission work?

Is replacing the valve body expensive work?

How do I identify if I have a 4T65-E transmission?

What would rebuild transmission mean in such situations?