radiator drain plug

It probably doesn't have one, That has been a common of and on thing with later model vehicles. I know most C/K trucks have been without, but unsure on the specific years. The way I drain the trucks, is at the water pump. I usually pull one of the heater hoses off of the pump, this will drain the coolant from most of the block(behind the thermostat). Then you can either pull the lower radiator hose off at the radiator, or the thermostat housing, to drain the radiator.