One problem related to noises during shifting has been reported for the 2000 Toyota Tundra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2000 Toyota Tundra based on all problems reported for the 2000 Tundra.
The transmission occasionally made a clunking noise and felt like the tire hit a small pothole in the road when shifting into overdrive. This started around 80,000 miles. I had the transmission fluid changed and the transmission pan dropped. The pan magnets had mostly small metal shavings but also a few larger pieces around 1/4" long. Now at 85,000 miles the transmission makes a very loud thud noise and shakes the truck violently every time it shifts into overdrive. I am forced to keep the truck in 3rd gear until I reach the freeway and then must press the o/d switch to shift into 4th gear/overdrive. My mechanic will be replacing the transmission next week as he has been on vacation. I cannot believe that the transmission must be replaced at only 85,000 miles! I am a careful driver and conscientious about maintenance.