Scotty, you're my go-to prof at YouTube University. I have a 2007 Toyota Sienna CE with about 140 thousand miles (not kilometers). Warm or cold, between 1400-1500 rpms, the van makes a low growling noise accompanied by a very slight vibration you can feel in the gas pedal and the steering wheel. It does this as the rpms move up and down in every gear. The engine starts instantly and purrs like a kitten above and below that speed. I've changed the engine oil and filter and drained half of the transmission oil and replaced it. No change. With the van up in the air, we used a stethoscope to listen to various parts. At all engine speeds we heard a high pitched whining sound when we put it on the oil pan - not normal according to the shop teacher at the high school where I work. Are these two different problems??? Engine? Transmission? Alternator? Any suggestions... cheap or scary?