Grafdakka's attack is more or less [url=http://typemoon.wikia.com/wiki/G%C3%A1e_Bolg]Gae Bolg[/url] in giant drill form, but instead of piercing one's heart, it alters reality to mulching anyone struck.

The issue isn't really "Could Grafdakka survive Torag's attack" because frankly, he probably wouldn't. At the very least Grafdakka would survive, but he wouldn't be able to shrug it off. The real question is "Can Torag face-tank Grafdakka's attack" because as mentioned, it's not just sheer ripping power it's channeling, but altering fact and reality to ensure that anyone caught at the business end of the drill [i]is[/i] mulched to death. Even should Torag's armor survive, there's still the possibility that Grafdakka rips apart the spiritual being inhabiting it due to the aberrant nature of his attack once fully charged.

Also Grafdakka's development as a mech is a fairly recent thing. So far in all past battles, Grafdakka has never been piloted before, and has simply been a giant robot warrior. This would be the first time the body of Grafdakka is being piloted, so even if the mech itself is severly damaged, so long as the entire thing isn't obliterated Endian could still slip out and continue the fight (Or repair Grafdakka so she could use him again). So I'm not too worried about Grafdakka getting severely damaged or destroyed, beyond what Endian inside might have to do. She hasn't installed an eject switch yet, so should Grafdakka be rendered unable to fight she'll just have to cut her way out.