Re: WJ 4.0 Coolant Leak
Check the coolant overflow bottle as well. Remove it and clean it out if necessary and look for any funny microcracks.
The liquid can run down the radiator mount and mislead you as to its source.
The radiators are infamous for cracking both at the core/tank interface but also at the lower outlet. If it is the radiator, suggest trying an aftermarket.
The water pump usually just weeps a bit, but if it has been weeping long, it might show a puddle.
Drop some dye and coolant and get a UV light, and pressure wash the engine to remove any false leads.
Or, pressure test it...