I just had my sunroof repaired on my 2005 Ltd 4runner. They replaced the plastic cable that pulls and pushes the roof. The plastic got brittle due to heat and wet weather. Toyota upgraded this cable to a tough steel cable version. I didn't pay for anything as my truck is still under warranty (less than 36k miles). The repair guy, a young Japanese Toyota engineer sent by Toyota HQ here to learn about common US problems with Toyota cars, said that the weakest part of past 4runners is the cabling for the sunroof.