I also have a 2005 sequoia.
I also have a 2005 sequoia. My frame has extensive rot including a large hole in the driver side frame. I brought it in to the Toyota dealership and it instantly failed the rust inspection warranting a frame replacement. The next day they cancelled the replacement and stated that the warranty for the complete frame replacement expired but they could still spray the frame with anti-corrosion material. They decided against spraying it because the rot is already to extensive. I feel cheated considering I bought the car w/in the past year and never received notification about the expiration date. The engine still runs great too.