LIke other problems reported here in various categories, this manifests as a whining or whistling noise under the car when it's in motion. Rear differential has to be replaced. The part alone is almost $5000 new from the dealer. A used one will be about $2700 installed at the local mechanic. This is not something I had planned on doing, but at least I got a lot of miles out of it before this happened.

This is the same part that Toyota has extended the warranty for on the Rav4, but not on the sienna (same part same problem). This part should not be going bad on a vehicle with under 100,000 miles on it that has been maintained at a Toyota dealer for all suggested maintenance. I spoke to a Toyota rep who told me since Toyota hasn't issued an extended warranty there is nothing they can do. The rep would not put me in contact with anyone who makes any sort of decisions for the company.