4WD is locked 50/50.

AWD depends on the year and transfer case number. The 2003+ Denalis and Escalades have a 50/50 (operates like an open front to rear diff so it can be anything under power in low traction situations). The stability system (when armed) applies the individual wheel brakes to control front or rear (or left/right) wheel spin. The 2002 and back Denalis and Escalades (as well as Syclones, Typhoons, and AWD Astros/Safaris) have a torque biasing T/C that can apply, in any infinite percentage, power to the front wheels as needed. These operate at a 65R/35F bias under non-slip condition.

Not sure about the 2003+ SSS....but I thought they were the same as the Denalis and Escalades.

Whew!