Turned out it was the shift solenoids- as the DTC indicated. $220 for the kit and labor. Thought I got off pretty cheap. The place is a local transmission franchise in the Minneapolis area. These guys are really decent and never try to rip me off. A few years ago the tranny in my collector car- a '67 T-Bird was leaking out all its seals. Chassis and trans had 120K. Engine only 10K. Anyway, they dropped the C6 out of the Bird. I asked if I should just rebuild it since it was out of the car. They looked it over and said the C6's were built like tanks. As long as it never got over heated or run out of fluid, they recommended just putting 4 new seals in it and put it back in the car! $300 for that.

Gotta do some TLC on the STS though this spring. She needs new plugs, and few other little putzy stuff.

you have to drop the trans to get off the side cover, right? i have a grand prix that needs a pcs and the job sounds similar. what type of $$ for labor did they charge you?

you have to drop the trans to get off the side cover, right?
No, you can lower the cradle a little and get at it. That said, the shift solenoids are accessed via the lower pan.