Does the 2006 4Runner have a timing belt or a timing chain?

Depending on Your engine configuration, Your 2006 Toyota 4Runner may either have a timing belt or a timing chain. The smaller 4.0L V6 engine utilizes a timing chain under the cover, whereas the larger 4.7L V8 has a timing belt. If You have the latter, it's recommended that You replace every 75,000 to 100,000 miles. The timing chain, on the other hand, is typically good for 250,000 or more miles -- typically, for the entire lifetime of the vehicle. If it does happen to fail though, either by stretching or other damage, You'll be looking at a lofty replacement cost -- the procedure can cost up to $3,000. The timing belt swap usually comes in under $1,000, so as with all things, there are trade-offs.