Rogue, I may take you up on that, but I was hoping to get someone local to plug in and see what is happening while the PCM is on the car. - if you were less than a 5 hour drive, I would have been there yesterday!

Hopefully you can find someone local that can help you out. If not we will be happy to take care of you if you decide to go that route.

**UPDATE**
So driving today, I jumped on the car and it easily revved up to about 5850 in first??? I then tried again, only this time shifting manually - this time only revved to 5200 before shifting on its own. So I'm thinking there must be some kind of governor sensor override that shifts the car automatically whenever you try manually? Does this make sense?

there are many paramaters that determine shifts

i would have to say that the the PCM will command the shift at a set point when the car is put in to Manual 1st. kinda like a fail safe. Also the speed of the car is used and there may be a different setting in the PCM to protect the Trans when in Manual First

Yeah, if I manually shift my car from first to second, it shifts at a lower RPM, but if I start it in second, it'll redline in first and I can hold second as long as I want to.

Our transmissions have much programming as mentioned.

If you put the car in second from a stop. You will start off in second and stay in second with no shifting. If you hold the car in first it will shift to second.

That seems counter-intuitive. Why did GM give us a gear selector that includes 1st?

Because ???

If you rev too high..it'll shift. However 2nd gear is that way to have second gear starts w/o dealing with a seperate button.

Because if I shift it to first I want it there until I decide to shift.
If they were worried about over-revving, why wouldn't they have simply programmed the rev limiter into the PCM? First they come out with idiot lights, now we've got idiot shifters?

No, there is a rev limiter as well.

There are many many different parameters to look at for any change in the pcm.