I probably shouldn't jump in here, but it sounds a LOT like a head gasket (or even possibly a cracked block) situation-since you've already replaced the radiator, I would wire the coolant fan to run continuously whenever the engine is running, (& I'll catch grief for this) pull the thermostat temporarily to INCREASE coolant flow until you can replace the water pump & diagnose what else is causing the overheating. This might even be enough to help with your transmission problem, at least until you get your S-10 straightened out.