[Technick]

Traction controll will have No effect on any gear change. The traction control takes a look at the wheel speed sensors, (same sensors used by the ABS system) compares wheel speed to vehicle speed (sensor is on the trans) and applies the brakes, (rear only) and I believe also dumps some ignition timming to control excessive wheel spin. TruBluePony is right in that it can be turned off manually enerytime the car is started. So since the Traction Control looks at speed sensor and wheel speed sensors, it has no idea or even cares what gears are in the rear end. The stock 8.8 has 3.27:1 gears and you can go as steep as 4.30:1 on the street if you want. The computer will need a custom chip "burned" or a ratio adapter installed for the speedo to read correctly after the gear change. There is no speedo gear anymore! Usually the chip metod is beter as the ratio adapter for the speed sensor will also affect the cruise controll operation. The cruise controll really does not know what mph you are going, it just tries to mantain a set speed based on reference to what the speed signal was at the time the cruise contol was turned on. The waveform pattern that the speedo see's is different than the waveform that the cruise controll see's even thogh the same speed sensor is used. That is becuse the ECU changes the signal from the speed sensor to the speedo, and changes it to a different waveform for the cruise control.
Is'nt electronic fuel injection great! Ah the marvels of modern technology!