Originally Posted by hotleadsingerguy
Actually that's not how most traction control systems work. The reason is simple: if your car is on a solid patch of ice, all drivetrain-engaged wheels would spin at close to the same rate. If it were checking purely for the differential between the drive-wheels it wouldn't see much of a difference and thus wouldn't engage the TCS. Most traction control systems operate with a variety of factors.
Another possibility, however unlikely, is that when engaging the clutch from a stop it puts more power to one wheel than the other. The TCS would engage to fix the differential. Like I said, I highly doubt an issue like that would exist on a large scale without Ford taking notice or at least admitting the issue.
As for the rest, I turned TCS back on and it shuddered at the next stop. Turned it off and the shudder is once again gone (at least reasonably so, as I've said). With the TCS off it performs like every other dry dual-clutch transmission I've driven in the past...which means I would have to assume *THAT* is how the car should drive. Very little slippage, but just enough to maximize engine efficiency at takeoff. While driving I experience none of the issues I normally do (taking turns at slow speeds shuddered the engine like crazy and I've had no such issue with TCS disabled).
And of course this is all speculative assumption, beyond the physical change in operation. Why it does it? I couldn't possibly say for sure. I can give my opinion, which is probably not too far from the truth, but I can't say for sure it's the 100% truth as to what is happening. That's for Ford to determine. Until then, I'll keep presenting my evidence and let them keep shooting themselves in the foot by lying to me
You're probably right, but as the Focus differential doesn't lock, the wheels wouldn't spin at the same rate on ice, would they?
I hope this is a good clue for Ford (that they need help from us is another story altogether) but turning the TCS off didn't change my car's behavior a bit. Too bad.