Water pumps normally have a weep hole and will leak when they start to go bad.
Start the jeep up, let it come up to temp to open the thermostat, once its is up to temp, rev the motor, if the coolant gets sucked down, then your pump is most likely fine and your thermostat is good too. Anymore stats are designed to fail in the open position but, not to say they always fail. While doing this see if the lower hose sucks in, compresses. Could be a weak hose squeezin closed under load.
Thermostat is easy to change/remove. The pump, don't know myself about that someone else will have to chime in.