Couple new problems with the truck?

Hello all, I've had a few problems with my truck lately and need some opinions ....
First off, i blew up my rad last week while driving on the highway. It separated on the bottom along the plastic seam. Once i had slipped a spare rad and new coolant in the truck, i replaced the degas cap and put a inline pressure gauge off the the degas bottle to see if i have pressure over 16 psi.
Sure enough i do, It will stay down below 10 if i am nice to it but as soon as i get on the throttle, it goes up quickly. I figured the gasket failed and drove the pressure in the cooling system way up, then my degas cap failed causing my rad to explode. Now, I'm fairly certain the evidence points to the head gasket being toast, but i wonder if there is anything else that can contribute to high pressure in the cooling system. Its not using any coolant and not over heating, there is no oil in the coolant either. Are there any other ways to test for evidence of a head gasket? also noticed after the blow up that the trans temps would warm up fully within a couple mins of it idling. It will warm up to the middle of the dash gauge and rest there without it even driving. It doesn't seem to get any hotter than that while driving , but it seemed weird. Warms up within 30 seconds after start at idle. changed both trans filters the fluid that came out. it had no effect. It is delayed into reverse and sometimes drive as well.
Trans cooler?
Thermostat?
Water pump?
Blockages?
Any thoughts?

I have the mods/upgrades in my signature.