Based on what you're saying, it sounds like it may be a bearing within the transmission or the differential. Also, it may be as simple as a transmission or engine mount that has collapsed causing the transfer of engine / transmission noise to go throughout the vehicle. If you have your oil changed at a quick lube, have them check the drive line fluids (transfer case / differentials). Also, ask if they can check the transmission and motor mounts while they are under the vehicle.
Let me know what you decide. I'm interested to see what they find.
Good Luck,
Joe
Wednesday, October 1st, 2008 AT 6:34 AM