This is such a fun subject.
To aid in understanding TC (traction control) vs LSD (limited slip differential). Some Ford Lightning owners complain of smoking only one tire off the line after 60,000 miles. This occurs when the limited slip has passed is't useful life. It can no longer split traction to both drive wheels as designed. The Lightning uses identical LSD technology. When the clutches wear out the differential is now 'open'.
TC for the Transit is not a torque vectoring or racing type of system. It just tries to keep the vehicle wheels spinning at the same RPM. It does this by decreasing engine output as well as applying brakes to match the opposing wheel's RPM. TC does not care what hill you attempting to climb or how slippery your driving surface is. TC is a safety feature, that's it.
TC shoots LSD's in the foot. LSD's require a loss of traction to work. When the wheel with less traction begins to spin, the clutches clamp down. The clutches transfer power to the non slipping wheel; therefore limiting the slip. That is it.
When decelerating, an LSD can also keep the vehicle straight in a hard braking situation or on decelerating on slippery stuff. If one drive wheel begins to lock up, the clutch pack clamps down and makes the non-spinning wheel spin. As far as I have read, TC does not intervene unless the power is being applied. The job of ABS is for deceleration and can never be turned off; whereas TC can. ABS can't make a wheel turn and neither can TC. Only LSD or similar can perform this safety function.