NewEdgeStang00

I've had the car back for a week now, did a full rearend rebuild from Ford with 4.10 gears. It's a 2001 GT AUTO. At first everything was good.

Just today, it started making a grinding noise when coming to a stop. It's fairly off and on. On other threads people are saying it's probably the clutch packs but I had brand new clutch packs installed from the Ford Racing TLok rebuild kit. The grinding noise actually sounds like it's coming from the front, but because of how short it lasts it's hard to pinpoint exactly.

I'm hoping it's just part of the break-in period and that this noise goes away. If it persists or gets worse after a couple weeks then I'm going to have it checked out by the mechanic.

Syracuse315

Stock LCAs?

CaptainRon

from a stop turn your steering wheel sharply to the left or right all the way then go ahead and take off and note if theres any clicking or grinding noises from the rear.
jack the rear up and spin the wheels and try to hear for anything abnormal.

and finally what I would do is to bounce the rear of the car several times while its in park real good and see if you hear anything, this way you can try to narrow it down to the cause.

Syracuse315

I'm trying to track down a noise as well (which I believe to be the LCAs). Listen for it @ 1:00:

http://www.youtube.com/watch?v=Q-Jex...layer_embedded

Sound similar to yours?

TRUEBLUE3934

NewEdgeStang00,
Who did the work on your differential?
I would strongly suggest taking it back there ASAP. This noise is not part of a normal break-in.

More details. Did it make any noise at the beginning of the week? Do you hear noise under any other conditions? Was the correct fluid used when the work was done? It is amazing how something as simple as the wrong fluid can cause terrible noises from the diff unit.

Good luck and post up any more info you can provide!

Syracuse315

This includes not putting in a friction modifier with the gear oil.

NewEdgeStang00

Thanks everyone for the help. A ford mechanic did the job for me and we used royal purple gear oil, I'm not sure if he used friction modifiers. There was no noise the first week while driving. I've been listening closely now and it sounds like it's coming from the front. And yes stock LCAs, also to mention its been lowered on hr ss, eibach prokit shocks n struts, maximum motorsports cc plates

NewEdgeStang00

Syracuse, sorry unfortunately that's not the noise I'm hearing. It's more like a crunching noise like metal against the brake rotors.

TRUEBLUE3934

Probably NOT the same issue for you, but my AuburnPro diff began making a TERRIBLE clunking/grinding noise and sounded like it was going to come apart at any moment when maneuvering at lower speeds. It turns out that the fluid I was using was WRONG!

I had installed Royal Purple Synthetic 140-85(I think). I spoke with an engineer at Auburn, the diff was designed to run a non-synthetic 80/90 fluid plus Ford Friction Modifier. I drained/flushed the Royal Purple and put the basic 80/90 dino oil in and the noise went completely away. I was shocked!!!

I share this just to make a point that the diff was designed around a certain fluid and using something else could cause terrible results. Note: my noise did not begin immediately either. It took a couple of weeks for the noise arise.

GOOD LUCK figuring this issue out!

Syracuse315

Figured that when you said you had the stock LCAs. And the hunt goes on...