File an official complaint with the National Highway Traffic Safety Administration (NHTSA): https://www-odi.nhtsa.dot.gov/VehicleComplaint/. Toyota won't respond to us individually.Same problem. I have a 2001 Sequoia that we bought new from the dealership. It has 140,000 miles. The dealer did the undercoating back in 2013-2014. Just found out that the frame has rusted away.