2002 Jeep Grand Cherokee Noise


#1

I have a 2002 jeep grand cherokee. lately there has been a weird high pitched rotating “squeel” coming from underneath the car when I bring it up over 20mph. It will slowly start when I accelerate over 20mph, and slowly fade when I decelerate under 20mph. It’s almost similar to the sound of a balloon when you pinch the valve and slowly let the air out, that “sqeeeeeeeee” type sound, but this is in a more rotating fashion. Almost like a bad belt would sound but more high pitched and more distinct.

We thought it was something in the Front Drive Shaft, so we replaced it. $600 and 3 days later the noise has returned.

It generally starts after I have been driving for 15 minutes or so and is loud enough to hear over the radio.



Like a very fast: “whirrwhirrwhiirwhiirwhiirwhiiir” from under the car.

The faster I go, the faster the noise “rotates”.

at 50mph its a steady “whiiiiiiiiiiiiiiiiiiiiiiiiiiiiii” sound.

When I slow down to 20mph,…the noise slows…



Any ideas what it could be? We put it up on the lift at my mechanics, and reved the engine but found nothing,…it seems to be specifically when the car is “moving”.


#2

Some possibilities/wild guesses:

  1. Loose brake pad contacting the rotor
  2. Differential noise (front and rear need to be checked). Low gear oil level could cause this. Unfortunately, once the noise starts, simply adding gear oil usually won’t eliminate the noise (damage has been done).
  3. Transfer case. Same issue as #2.
  4. Vacuum leak.

Would it be possible for you to post a sound file with the noise? That would make diagnosis a lot easier.