2003 GMC Sonoma Owner's Manual - Page 248

Dolly Towing Shidting a four-wheel-drive vehicle's transfer case into NEUTRAL can cause your vehicle to roll even if the transmission is in Park (P) for an automatic transmission, or if your vehicle is in gear, for a manual transmission. You or others could be injured. Make sure the parking shift the transfer brake is firmly set before you case to NEUTRAL. If your vehicle has four-wheel-drive it cannot be dinghy towed. A four-wheel-drive vehicle must be towed by flatbed. I Two-Wheel-Drive Vehicles Only Nofice: Towing your vehicle with all four wheels on the ground will damage drivetrain components. Your two-wheel-drive vehicle should not be towed with two wheels on the ground. Your transmission has no provision for internal lubrication while being towed. To properly tow your vehicle, it should be placed on a platform trailer with all four wheels off the ground. Towing with all four wheels on the ground should be avoided. 4-47