Coolant leak rear of engine

Hello all, I need some help. I just replaced radiator and thermostat to solve coolant leak issue, but now truck will not hold coolant at all and is leaking from presumably new location at rear of engine. Literally just pouring out. Never had a leak problem like this before. No white smoke out of exhaust or leak in passenger side of cabin. Pics included.4.0l 6 spd. double cab.

 

When you did the thermostat you may have slightly dislodged the crossover pipe that goes in the valley between the heads, or the new coolant could have been the minute change for the o-rings on that pipe to give way. I'm not certain, but it would be my first guess based on the location. Also check the lines going to the heater core

 

A hose off
Head not torqued down
Crack in block

 

Pulled off the intake as per your suggestion. Likely dislodged the pipe on the back of the water pump, or at least that’s where it’s coming from as I can see moisture at the top of the valley between the heads. Any tips on how to replace that hose?

 

Just found your post I'm having same symptoms, found my leak around the heater core hoses.