Rear Axle "Rubbing Noise"? Anyone

[Prodigy603]

So in the last week, I have begun hearing a rubbing or whining noise coming from the rear axle of my 2011 GT500

It is only noticeable when the car is making tighter turns at lower speeds (like driving around in a parking lot or neighborhood), but seems to change pitch with speed.

Among a few other "check-ups" I took it to the dealer. After doing some checknig they say it is "Perfectly normal, on '07' thrus '11's due to the carbon fiber clutches in the limited slip differential to experience noise from the rear axle"

He went on to say that "driving the car in 5 figure 8's may alleviate the noise temporarily"!!!

Has anyone else experienced this noise or been given the "it's normal" routine?

 

[CPRsm]

I think even as far back as 05, but yeah, it's the diff. Throw another bottle of FMS clutch treatment in there. Iirc, there was even a notice out about it.

 

[Prodigy603]

I think even as far back as 05, but yeah, it's the diff. Throw another bottle of FMS clutch treatment in there. Iirc, there was even a notice out about it.

Hmmm. As someone enjoying getting used to the GT500 after coming from a Vette, this seems odd. Or atleast sounds odd.

I guess I'm relieved that there is nothing "wrong" and realize that with performance parts come some concessions, like rougher ride or squeeky breaks (don't have that) all in the name of performance.

Not to sound ignorant, but what is the FMS clutch treatment? Where do I get it? Where do I put it in?

thanks in advance.

 

[SicShelby09]

Hmmm. As someone enjoying getting used to the GT500 after coming from a Vette, this seems odd. Or atleast sounds odd.

I guess I'm relieved that there is nothing "wrong" and realize that with performance parts come some concessions, like rougher ride or squeeky breaks (don't have that) all in the name of performance.

Not to sound ignorant, but what is the FMS clutch treatment? Where do I get it? Where do I put it in?

thanks in advance.

Friction modifier. Take it to ford and they should take care of it for you.

 

[Prodigy603]

Friction modifier. Take it to ford and they should take care of it for you.

If it is still at the Ford dealership. What do I need to ask them to do?

"Put in a friction modifier in?"

Is that covered under warranty, or should I expect to get bent over to put it in?

 

[ad445]

This was exactly my problem with my non svtpp 2011 gt500 that i had before this one loool. That car made all kind of noises from rear axle and 1st to 2nd gear problem. Dealership said the exact same thing abt carbon fiber thing. I got sick of it and traded it in for SVTPP and not one issue thank god lool.

 

[oldlugs]

IT'S NORMAL if you have the carbon-fiber diff clutches. Drive slowly doing some figure 8's, and they should loosen and quiet down, 'till the next time you get on it... I wouldn't add friction modifier to quiet them... I think it would just make your limited-slip, slip more. Both my KR and my Bullitt have the same diff, and both made the "groaning, dying whale" sound when I first got them. I don't notice it so much any more.

 

[Prodigy603]

both made the "groaning, dying whale" sound when I first got them. I don't notice it so much any more.

You nailed it. That's the sound exactly. I can not completly picture the mechanics to understand why the figure 8's will help reduce the noise.

Is the Friction Modifier something I can add or should I have the dealer take care of it...if so, do I need to specify a brand or will they know exactly what I am asking for?

Are there are any other side effects from the friction modifier that may cause a worse scenario? ie: no more dying whale noise, but know it sounds like sand paper over glass, etc.

 

[oldlugs]

You nailed it. That's the sound exactly. I can not completly picture the mechanics to understand why the figure 8's will help reduce the noise.

Is the Friction Modifier something I can add or should I have the dealer take care of it...if so, do I need to specify a brand or will they know exactly what I am asking for?

Are there are any other side effects from the friction modifier that may cause a worse scenario? ie: no more dying whale noise, but know it sounds like sand paper over glass, etc.

With the torque these make, shifting hard seems to jam the diff clutches together, locking them. Figure 8's seem to loosen 'em up again, as will normal, gentle driving. Friction modifier just makes the clutches slip more, if I'm not mistaken. You can add some yourself. Ask for it at the Ford parts counter, or order online. I wouldn't add it though... Live with the sound for a while, and don't worry unless your rear starts to either whine (loudly) or growl.

 

[CPRsm]

You nailed it. That's the sound exactly. I can not completly picture the mechanics to understand why the figure 8's will help reduce the noise.

the noise is the clutches. the clutches only slip or make noise/chatter when they release and let the tires move at different rates. Like when you go around a turn. So to speed the provess up to get them to seat faster and wear into each other faster, you similate turns and making the diff break lose by going around in figure 8's in different directions. I have to do it with currie limited slip for the early fords. Those chatter pretty good. Takes me about 10 mins of driving in a parking lot to get it to quiet enough to where the customer won't freak out the first time he makes a turn. Still makes a noise, but not like when I first put it in.

 

[Prodigy603]

Thanks for the advice and explanation. Picked up the car tonight and this weekend I will be taking it to the local high school for some figure 8's!