Intermittent Driveline Screech Noise

Rick10

New Member
Apr 3, 2005
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Knoxville, Tn.
First I'd like to comment that this forum has been very helpful to me in the past, I appreciate those here who take the time to help others having problems.

OK, here is my problem. I put new 3.73 Ford Racing gears in my 2000 Mustang GT Convertible, which was completely stock. I got the backlash to .011", and I got the pinion preload at 15 in lbs, with one .030" shim, which was only different from the stock shim by .001". I crushed the crush washer with great difficulty, and stopped when I got to the 15 in lbs of pinion preload torque.

Anyway, it is quiet on the road, quiet on turns, EXCEPT, everytime I drive the car, it will make one big screeching noise, within two to 10 miles of starting the car. It sounds like metal on metal. The screech follows the wheel speed, it will stop only if I stop the car, it is not engine or clutch dependent. It gets real loud for a few seconds, then if I just ignore it, it gets quieter and goes away, and never comes back, even if I drive 50 miles, on the road or in traffic. But when I stop, even for just 20 minutes and start the car and drive again, it repeats the one event very loud driveline screech. It will start at almost any speed, and go away in roughly the same amount of time, roughly 15 seconds.

I have tried stopping and driving in reverse, but this will not make it happen again. I have to shut down for about 20 minutes for it to happen again.

I have checked the rear brake calipers and anchor plates to see if they are hitting the rotors. They are clear for the full axle axial free play, which is less than a mm on both sides.

Anyway, this itermittent, one time per drive loud screech has me baffled, and of course the car is unmarketable with this sound. Being a convertible, it is really loud with the top down. Any help is welcome.
 
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Try raising the rear wheels and securing them on jackstands.Run the car and see if you can figure out whats causing it that way.You could also tear the rear end down and look for what would probably be a severe wear pattern on something.
 
Chopper1,

I tried the jack stands in the garage, and it made the noise once, and it sounded like it was coming from the left rotor, but I really need two people, one to drive and the other to listen. Then it would not make the noise again.

I will pull the diff cover tonight.

I'm thinking another possiblity is the U joints, but they should still be good at 36,000 miles.

Rick10