It is hard to test the heat of your GPU on a console. Especially the first generation of the Xbox 360 consoles had heat issues which could resolved in damaging the RAM aka the known ring of death issue. You can try to setup your console "open air" as possible, without anything which could block the air-flow and try to carefully clean the console from dust. It could be the HD as well but please keep in mind that if you replace the HD, Titanfall will only be playable with an official MS Xbox hard drive.
Just from a feeling, is the console getting more "hot" while playing TF than other games?
Cheers
Basti