I have a 2008 Rav 4. 86000 miles and serviced vigilantly. Before the warranty ran out it had a problem that no one could diagnose so now it's out of warranty and the problem is a lot worse, still no one has a definite diagnosis. Toyota is not honoring it's extended warranty, so I will be paying out of pocket so it would be nice to have a better idea of what the problem could be.The rattle was very intermittent at 40mph going up a slight hill. If I took my foot off the accelerator and put it back on the noise went away. Now it is rattling quite a bit and not just at 40mph. I can still have it stop for a bit by taking my foot off the accelerator and putting it back on. My mechanic told me to try driving in 3rd gear. It has not rattled in 3rd gear yet. Toyota mechanic of 29years has never heard this noise before and neither has my mechanic so it is an unusual one. Toyota wants to do a transmission flush 3 times and then if that doesn't fix it will put in a new transmission. My mechanic thinks it is the transfer case. No one knows for sure. Does anyone have any ideas?