This qouted from this website:
http://www.truckworld.com/Truck-Test...y2k-chevy.html
Overall ride, handling and turning diameter have been improved. Significant trailer towing enhancements include Premium Smooth Ride Suspension and Autoride "Real Time Damping" Suspension. The former (optional on K1500 Series) features self-leveling rear shocks that use energy from normal suspension ride motion to adjust and maintain level vehicle trim heights and help improve handling. The latter is a fully-automatic system which utilizes information from wheel height, steering and other sensors to continuously vary shock damping while driving. Electronic sensors control a compressor pump that keeps the rear of the vehicle level with the front. Suburban (and Silverado) also offer pre-wired trailer connections, pre-wired brake controller, Tow/Haul mode on the transmission to adjust shift points and dynamic rear proportioning that helps maximize rear brakes while trailering.