theres some palm muting after the solo, generally a good method to tell is to try to emulate the sound with your voice, and if you end up going like "chugga chugga" or like "guh guh guh guh" its a palm mute. and hes definitely going back and forth between muting it and unmuting to give it some dynamics. as the for the tone change, it sounds to me like he either has 2 distortion channels on his amp, and one is louder (for soloing in this case), or he just has a distortion pedal or something with the output pretty high so the volume kicks up when he steps on it.
Thanks dude, Ill try a few things and try to figure it out.