I just purchased a 96 Landcruiser. I recently noticed a hum sound coming from the rear of the vehicle when under load. The sound goes away when you let off the accelerator. Occurs between 60 to 70 mph. I took it to the local toyota dealership and they indicated the rear end should be replaced. The $1500 repair seems crazy considering they could not guarantee this was the problem. Has anyone else had this problem? Vehicle has 111k miles on it.