Strange oscillating noise at 20-25 mph
 

My ‘83 300TD developed this intermittent oscillating high pitched sound that comes in around 20-25 mph. Here is what this squealing sounds like - Weeeeohweeeeeohweeeeoh. The strangest part is that it comes in randomly. Any slower or faster it goes away. Brake pads and rotors were replaced 2000 miles ago, and this sound just started to show up recently.

I'd put the front end up and see if i could get any sound moving things around and spinning the wheel. Could be wheel bearings or the dust shield dragging on the rotor.

Is it temperature dependent? Only when car is cold, or worse when cold?

Speedo cable. Or possibly speedo itself. Mine is louder when cold.

Can you record a video and upload it to Youtube?

That will help a lot in deciphering the noise.

I jacked the car up today and did not notice anything out of the norm at all four wheels. I noticed that the sound is more towards the rear. I’ll try to video the sound.