Checked the tranny fluid.

Fluid is dark, but still definately red. Smells like tranny fluid, but maybe a wee bit burnt? Make sense?

If it ends up not being your trans, which hopefully its not, you should change the fluid in your trans and consider installing a trans cooler. As for your problem it could very well be your trans. However I had an O2 sensor that did very similar, when I gassed the car it jerked spit and spuddered, and all sorts of strange stuff. How is your gas mileage? Anyhow you need to get the codes to know for sure I guess

Gas mileage is sucking atm. I did pull the codes.. nothing there.. just code 12'* over and over.

When you had the O2 sensor go bad, would it jerk and sputter at any speed, or just lower? Car runs fine at higher speeds, and in reverse.... which is why I'm thinking it'* the tranny.

Still find it odd that I never had a problem with it at all, till today out of the blue, and it was after I got it back from the Dealer for an oil change...

alrighty then..

IF it does turn out to be the Tranny, which tranny do I put in?

Did a search for junk yard ones, and it asks for things like w/traction control or w/o, w/ supercharger and w/o..

They didn't just put one type of tranny behind this engine? the traction control and supercharger changes it?

4T60 - E HD

When my O2 in my GA went it spit and spuddered through out the driving ranges. Also it went suddenly, one day it ran good, the next I thought the thing was blowing up. Also if it did it right after it came back from the dealer, and you find that they did someting to the trans or whatever, they should be the ones replacing the trans or the messed up part, but proving they did it could be hard

You really need to get a scantool on that while driving.

Update:
Drove it again this morning. Seems to drive better when it'* cold.. also, if I start off in 2nd gear, I have to rev higher, but no "jerking/stumbling"

While driving to Krispy Kreme, the SES light came on twice. Checked the codes, and it gave a 56 - Boost Control Solenoid.


Would that cause the other symptoms?

Actually for */c code 56 is quad driver "b" error...LIKE mine right now..I believe we may have same problem...1-2 shift solenoid error...inside tranny..does it not want to shift from 1 to 2...mine wont even downshift to 1st manually....shift solenoid is internal to tranny...from what I understand...you (WE) have to lower trans and access fron side cover to remove and replace solenoid(*)..I am going to replace BOTH since I will be there anyway...parts are minimal...12.00 each from GM...both parts w/ new gasket is like 65.00 for GM...GOOD LUCK

Yeah, that does sound like it... when it goes to shift from 1st to 2nd... it jerks bad or stumbles. If I start off in 2nd, then it'* ok, and I have no problem at all with any speed.

Good to know about those solenoids.

Guess I still need to take it to a tranny shop, and have them do a diagnostic while driving? Afraid they're gonna take the opportunity to rake me over some hot coals.