Originally Posted by PratoN
Good point that the latest flash affected ABS, I forgot about that. I'll have to try this, but I doubt it'll solve my issue.
Also, I don't think the wheel size has much to do with TC/ABS as long as all of the wheels are the same size since it's checking for tires slipping and not revolutions vs true speed.
I could see lighter/heavier wheels causing issues if it's outside of the car's expected loads / parameters... that said, I think we're experiencing a leaking clutch seal (internal, most likely, since I have no fluids outside my bell housing as of yet).
Well that's my best assumption (the last paragraph). There's definitely a possibility of the TCU noticing lower resistance on the drive shaft and assuming that the tires are slipping when, in fact, the tires aren't losing traction at all. At that point it would engage the TC and feel generally as it does when the car "shudders". It makes perfect sense...but who knows if it's the truth.
As for the leaking clutch seal, that would only make sense if it just gradually got worse. My car was received in April of 2011, and I didn't have a single issue until after the TSB update that was performed in mid-June of this year. It started almost immediately after that point, got worse over the following 2 weeks or so, and then plateaued at that point and has stayed there ever since. It's almost as if the computer learned incorrectly and then held that programming.