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Hum from rear of car

I can hear it in the 5-40 range, windows up, radio off. If I roll the window down the wind drowns the noise out. The car has 6k miles and Torsen rear. Anybody else?
 
I have something sort of like that. It kind of sounds like if the car was 4 door that the back door wasn't fully shut. If I take my rear tire while parked and shake it, you can hear something in the suspension back there squeaking like crazy. We think it's a bushing or something of the sort. Taking it to the dealer Monday after work for them to look at it. So we will see. It could be the control arms as well seeing as people have had problems with those in the new Mustangs. I'll update as soon as I know more.
 
Drop the rear seats down and see what happens. My car has a metallic 'rubbing' sound. It's my ring gear. I am waiting for a replacement, which I am told won't be available for two weeks.
 
PTRocks said:
Drop the rear seats down and see what happens. My car has a metallic 'rubbing' sound. It's my ring gear. I am waiting for a replacement, which I am told won't be available for two weeks.

Really? I was told it was normal. ??? There are others that have the same sound. Did they pull the diff cover and see something?
 
BossJockey said:
PTRocks said:
Drop the rear seats down and see what happens. My car has a metallic 'rubbing' sound. It's my ring gear. I am waiting for a replacement, which I am told won't be available for two weeks.

Really? I was told it was normal. ??? There are others that have the same sound. Did they pull the diff cover and see something?

I can hear the sound reflecting off of walls when I drive by buildings. At first I thought it was the brakes. One day it became noticeably louder so I brought the car in. This is what they found:
Note the brown spots on the faces of the teeth at the center of the picture. If you right click on the image to view it in a new tab or window you can see it full size.

1314635639-random-pics-your-boss-302-p1020226small.jpg
 
BossJockey said:
I wonder if they had a bad run of ring gears? I guess I'm going to need to get my rear cover pulled.

In my case they test drove the car, (I had the rear seats down so the noise was evident), then ran it on a lift while probing with a stethoscope to localize the noise, then they pulled the rear cover. In my case that was three visits to the dealer :( Hopefully you can get it done in one shot if needed.
 
Yes exactly, it sounds like a metalic race pad dragging. Thanks for the tip. Do you have a Torsen rear?
 
PTRocks said:
BossJockey said:
I wonder if they had a bad run of ring gears? I guess I'm going to need to get my rear cover pulled.

In my case they test drove the car, (I had the rear seats down so the noise was evident), then ran it on a lift while probing with a stethoscope to localize the noise, then they pulled the rear cover. In my case that was three visits to the dealer :( Hopefully you can get it done in one shot if needed.

Did you ever get your ring gear replaced? Did it fix or reduce the noise?
 
I did and it did reduce the noise, though not completely.

I have another issue that cropped up after the service, now the diff (bites) when I apply some load while going around corners. Under no load it's smooth, but when loaded the diff chatters when it used to be smooth. My first thought was that the driveshaft wasn't properly installed, causing a variation in speed (and thus torque) at the pinion. The dealer has gone over the car thoroughly, and it's improved a bit but it's not fixed yet.
 

ArizonaBOSS

Because racecar.
Moderator
8,523
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Arizona, USA
I have the metallic "race pad dragging" sound as well. I have the Torsen.

I was hoping it was my ebrake not adjusted properly, but after releasing some tension from the cable the noise did not diminish.

The metallic sound is very apparent with the windows down while cruising in low RPM, especially next to curbs or walls. Definitely more evident with the rear seats down. It's very apparent that it is speed-related. I put the rear of the car on jackstands and let the car idle in first through 6th gears...much louder at higher road speeds but same RPM.

I'll have the dealer take a look at it at some point. In the meantime, I will wait for more info here from you guys.
 
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I have the same thing going on.... A metallic constant rubbing sound. Like a "race pad". I can hear it in the same mph range 5-40 mph. I changed my rear diff fluid at 1k miles. The noise started and I changed it again at about 2100 miles. I have about 3k miles on the car now and sometimes it makes noise and sometimes it doesn't. I will have to drive the car again to see if it does it. I am waiting for others to sort it out as well... I can't have my car in the shop all the time.
 
This is normal NVH guys. Put your rear seats down if you have a non-LS and you'll really think you have a problem. It's gear and axle noise, not to mention your floating rear caliper where your pads are always making some contact with the rotor even with no brake being applied. Welcome to the world of the live rear axle Mustang :p Just swap out your axle backs for some lighter (louder) mufflers and pull your side discs. Problem solved! ;D
 
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Gary I know you have told me this before. But the noise only started after one of my track days.... It has me a bit nervous. And further more not everyone is talking about it or has mentioned it. Everyone should be hearing it that it has the torsen diff...
 
adam81 said:
Gary I know you have told me this before. But the noise only started after one of my track days.... It has me a bit nervous. And further more not everyone is talking about it or has mentioned it. Everyone should be hearing it that it has the torsen diff...
Have you changed diff fluid? Ford says you don't need to add the friction modifier with the Torsen. Torsen's site says you don't need to either but that if you do it will help reduce noise from the diff if you add it. I didn't add it the last time it was changed.

In general, another reason for more NVH noise in the Boss is the elimination of 11 pounds of sound deadening material.
 
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Standard LSD here - not Torsen - and I have the same sound. Not very loud though. Just sounds like typical driveline noise to me, and since I have moderate hearing loss in my left ear (too much cranked guitar playing in my earlier years), I only hear it on the right rear. Considering my tight turning groans are apparently "normal", this driveline noise doesn't even phase me.
 

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