Big D wrote:
4WD Low Range
Partial Off This is the normal operating mode for ESP in 4WD low range. Whenever the vehicle is started in 4WD low range or the transfer case (if equipped) is shifted from 2WD, 4WD high range, or neutral to 4Wd low range, the ESP system will be in this mode. In 4WD low range, ESP and TCS, except for the "limited slip" feature described in the TCS section, are turned off until the vehicle reaches a speed of 30 mph. At 30 mph, the normal ESP stability function returnes but TCS remains off. When the vehicle speed drops below 25 mph the ESP ssytem shuts off. ESP is off at low vehicle speeds in 4WD low range so that it will not interfere with off-road driving but ESP function returns to provide the stability feature at speeds above 30 mph. The "ESP/TCS Indicator Light" will always be illuminated in 4WD low range when ESP is off.
Strait from the manual
Basically what that means is that in low range excess wheel spin is stopped "limited slip" but there is no automatic throttle reduction like you would get with full fledged traction control.