[SixtyHertzHum]

Just signed up, looking for help/advice.

I have a 2011 Mustang GT Brembo with 3.73 rear and carbon fiber LSD clutch plates (all factory, car is 100% as it came from Ford).

Around 32k the pinion seal went bad for no apparent reason. My dealership replaced it under warranty, but did NOT replace the crush sleeve when putting things back together. They also told me that Ford instructed them to not use any friction modifier in the differential oil.

Shortly there after the differential started to moan when making slow speed corners. I took it back to them, they told me that this was perfectly normal and that I needed to do the "figure 8" trick to get oil back into the clutch plates. I specifically asked them if this could have been caused by what they had recently done, and they said no. So I've started to do figure 8's a few times a week. I drive about 80 miles a day, most of it highway - this is my daily driver. Figure 8 trick only worked for a short time.

I'm now at 40k, and things have gotten considerably worse. The car moans and grinds around corners when warm. Right turns seem worse. The worst part though is that it has started to shudder at very low speeds, and this is made much worse if you are applying any torque. This also seems loosely correlated to taking off from a stop after downshifting, such as when I get off an exit ramp and turn right.

Any thoughts? I'm calling the dealer again tomorrow to have them look at it - again - but I'm loosing confidence. The car is great otherwise, but it's a total embarrassment to myself and to Ford when I'm in a parking lot and it sounds like I have 3 dying cats in the trunk. The way it sticks also makes me nervous driving this every day to work, and I've stopped taking long trips with what is basically a new(ish) car. Any remedies? Friction modifier? Pony up the cash for a Torsen?

 

[5LHO]

Get a $4 bottle of fricmod and add 2 oz at a time and retest for improvement. This has nothing to do with pinion seal, ring gear, backlash or anything other than diff noise. It's ******** to live with this, I know how loud it can be. Try this, there's nothing to lose and I'll bet you a dollar it fixes it right up for you.

If you don't have access, make a friendly drop in at your local jiffy lube or similar. Explain your situation and bring doughnuts. They'll probably help you out getting it in there for free after that.

 

[Sean Reilly]

I would NOT TOUCH Anything that the dealer already tried to fix, as it can be blamed on you!!......Bring it right back to the dealer, and (Nicely Demand) that you want a whole new Diff. ring and pinion gears, LSD carrier, the works!!.........If they refuse, contact Desha the Ford CSR that is probably going to read this thread anyway........You should indeed have no problem if she has to get involved .............Sean

 

[5LHO]

If you don't want to touch it, insist the dealer try this solution first, regardless of what corporate said.

This'll probably fix it and neither of you will have the "buy you a new diff" hassle.

I've been inside enough of these things to know what's up with them.

 

[stevegt2012]

I would NOT TOUCH Anything that the dealer already tried to fix, as it can be blamed on you!!......Bring it right back to the dealer, and (Nicely Demand) that you want a whole new Diff. ring and pinion gears, LSD carrier, the works!!.........If they refuse, contact Desha the Ford CSR that is probably going to read this thread anyway........You should indeed have no problem if she has to get involved .............Sean

Definitely this! Damage may have already been done.

Where did you get the idea that carbon fiber LSD clutch plates came in the GT rear end? And if it does have carbon fiber plates I think those are just supposed to be soaked in friction modifier prior to installation but the friction modifier is not subsequently added to the differential oil.

 

[SixtyHertzHum]

Definitely this! Damage may have already been done.

Where did you get the idea that carbon fiber LSD clutch plates came in the GT rear end? And if it does have carbon fiber plates I think those are just supposed to be soaked in friction modifier prior to installation but the friction modifier is not subsequently added to the differential oil.

I got this from both the dealer and a few places online concerning the details of the Brembo package. Ford sold it as a brake package in 2011, but there were apparently a lot of other little touches that came with it. I suppose they both could be wrong - I've not actually laid my hands on them.

 

[5.0 Candy REDCS]

I'm not sure if this helps,BUT when I bought my Dodge ram truck in 2003 I took it in at around 15,KM for a basic oil change...the new girl that was working in service also checked the box for differential oil change/NO friction modifier... when I went to pick it up, I noticed the additional diff service and basically told them I did not request it,I was not charged BUT the second I went to leave the dealership and tried to turn a sharp right...it sounded like it was about to blow right up AND it literally was hoping and chattering into that turn! I took it back in, they checked out my complaint and said friction modifier SHOULD have been added to the diff clutch plates,basically they toasted my entire diff,2 weeks later the new unit came in and was replaced under full warranty.Never had another issue with it,initially they said they were going to rebuild it,but I insisted I was not going to go for any rebuilt unit...
I do a lot of business with the dealership owner,and he just approved a brand new factory diff!
That was the last time I saw Rachel working there!

 

[ridenfish39]

Your clutch pack is toast...same think happened to me at 10k miles. They replaced it and I'm still chatter free at 15k.

 

[SixtyHertzHum]

Appointment has been made with White's Maibach Ford in Orrville, OH for later this week. My hopes are low, to be honest. I am going to try and get some under-chassis GoPro footage of the problem tomorrow or Wednesday weather permitting, and will make sure to update everyone here as things progress.

I would have no problem adding friction modifier myself, however I am of the opinion that this is a warranty issue and Ford should be taking all actions. I should share that I specifically asked the dealership about friction modifier and they in turn asked the Ford hotline, who told the dealership that adding the friction modifier was not advised. The dealership said they were told that it would change the friction point of the clutches too much. I found this response odd given that everything I've read on the carbon fiber clutch installation involves soaking them in this exact product as you pointed out - but again, for now I'm letting them drive so to speak.

If this isn't resolved by the time the warranty expires, then I'll decide if I use friction modifier or swap it out for a Torsen.

Looking forward to sharing video to show you what they're trying to convince me is "normal".

 

[5.0 Coyote]

I would contact Deysha BEFORE you go to the Ford dealership,that could save you one major heartburn,she always take"s care of us and cut"s through the red tape,Ford Customer Service will get you in contact with Deysha on this site.

 

[SixtyHertzHum]

I would contact Deysha BEFORE you go to the Ford dealership,that could save you one major heartburn,she always take"s care of us and cut"s through the red tape,Ford Customer Service will get you in contact with Deysha on this site.

Thanks for the advice, I'll try to reach out to her.

Hopefully I can get this fixed to the point where I have trust in the car again.

Thanks everyone for the help and advice - I'm very glad I joined and posted!

 

[FordService]

Just signed up, looking for help/advice.
I have a 2011 Mustang GT Brembo with 3.73 rear and carbon fiber LSD clutch plates (all factory, car is 100% as it came from Ford).

Around 32k the pinion seal went bad for no apparent reason. My dealership replaced it under warranty, but did NOT replace the crush sleeve when putting things back together. They also told me that Ford instructed them to not use any friction modifier in the differential oil.

contact Deysha the Ford CSR that is probably going to read this thread anyway........You should indeed have no problem if she has to get involved .............Sean

Definitely this!

I would contact Deysha BEFORE you go to the Ford dealership, she always take"s care of us and cut"s through the red tape,Ford Customer Service will get you in contact with Deysha on this site.

Hi SixtyHertzHum,

As the other awesome members have mentioned, I’ll be more than happy to help. Please send me another PM with your VIN, dealer, mileage, full name, and best daytime number so I can help.

Thank you, guys!

Deysha

 

[5LHO]

Honestly, I can't stand this passive strategy you're using. You've lived with this for thousands of miles thus, probably creating a greater problem, now you won't add the fricmod that should have gone in thousands ago because you "want Ford to take all the actions".

If you added this in the first place, regardless of what the idiot tech line said, you, wouldn't have done any consequent damage and you wouldn't have to schedule dealer appointments, hassle with warranty or "contacting Deysha", like that's a magic bullet.

There was no risk, fricmod reduces clutch plate drag so, you'd actually make the diff plate's lives easier, not harder. The way you have it now, it's brutally beating the **** out of itself in every turn. You'd still have warranty support, as no one is going to fluid analyse your diff oil to see if there's fricmod in it. You wouldn't have breached any warranty condition by adding it, either

The stock LSD is a regular fibre plate LSD and it bloody well needs fricmod on the road. Personally, I just did the change to Redline Shockproof in my '12 and I can assure you, some FM was needed to silence the diff. Not all the same though, I ran my last 5.0's 8.8 with a stacked clutch pack and no fricmod for years without issue, just the tiniest hair of chatter around really tight turns but no noise.

 

[SixtyHertzHum]

Honestly, I can't stand this passive strategy you're using. You've lived with this for thousands of miles thus, probably creating a greater problem, now you won't add the fricmod that should have gone in thousands ago because you "want Ford to take all the actions".

If you added this in the first place, regardless of what the idiot tech line said, you, wouldn't have done any consequent damage and you wouldn't have to schedule dealer appointments, hassle with warranty or "contacting Deysha", like that's a magic bullet.

There was no risk, fricmod reduces clutch plate drag so, you'd actually make the diff plate's lives easier, not harder. The way you have it now, it's brutally beating the **** out of itself in every turn. You'd still have warranty support, as no one is going to fluid analyse your diff oil to see if there's fricmod in it. You wouldn't have breached any warranty condition by adding it, either

The stock LSD is a regular fibre plate LSD and it bloody well needs fricmod on the road. Personally, I just did the change to Redline Shockproof in my '12 and I can assure you, some FM was needed to silence the diff. Not all the same though, I ran my last 5.0's 8.8 with a stacked clutch pack and no fricmod for years without issue, just the tiniest hair of chatter around really tight turns but no noise.

I appreciate your honesty. As mentioned above, I specifically asked my dealer about adding friction modifier, and they supposedly asked this directly to the Ford tech hotline who indicated that friction modifier should NOT be added. At that point I made the decision - however poor you may feel it to be - that Ford knows their own vehicles best, and I would try to move forward using their advice of doing figure 8's.

When that failed, I came here for advice. Right now I've reached out to Deysha and am hoping that my trip to the dealer later this week will prove more fruitful than the last, but that does not mean I am ignoring the idea of adding some if that doesn't work. I really do appreciate all the feedback on here, even if you disagree with the way I'm going about things. I've made the decision that since this is my daily driver I would preserve the warranty as best I could, but I understand your point of view as well - but I just couldn't add some after being specifically told not to by people who I would like to think know a lot more about my car than I do. For now I'll let Ford take another swing at it.

 

[stevegt2012]

I got this from both the dealer and a few places online concerning the details of the Brembo package. Ford sold it as a brake package in 2011, but there were apparently a lot of other little touches that came with it. I suppose they both could be wrong - I've not actually laid my hands on them.

I had to have the 3.73 ring and pinion replaced in my Brembo GT due to a whine. There is definitely a line item on the work order for friction modifier. So if they didn't put it in yours due to bad information or communication..... you see my point.

 

[5LHO]

in only 7000 miles (32k to 40k) on this you probably haven't worn anything beyond saving...if you added the fricmod you could try it and then cancel your appointment if it solves it....honestly, I'm so sure this'll solve your problem; I just won't shut up about it.

Then you can find another dealer, hoefully without non-thinking parrots in the service dept.

 

[SixtyHertzHum]

I had to have the 3.73 ring and pinion replaced in my Brembo GT due to a whine. There is definitely a line item on the work order for friction modifier. So if they didn't put it in yours due to bad information or communication..... you see my point.

Thanks for chiming in, Steve. As a fellow Brembo owner, any chance you can comment on the clutch material first hand? Rumor was that to get carbon fiber from the factory on a GT in 2011 you needed to order a Brembo with 3.73 gears. I have yet to find the official documentation from Ford stating this though.

 

[FordService]

Right now I've reached out to Deysha and am hoping that my trip to the dealer later this week will prove more fruitful than the last

Thank you for the PM, SixtyHertzHum! I'll get back to you as soon as possible.

Deysha

 

[SixtyHertzHum]

Update Time

I picked it up tonight. All they did so far was verify the fluid level in the differential, which of course was fine. They are apparently still on the phone with Ford concerning this, and fully expect to talk to them more on Monday. Thanks again Deysha (and Frank, regional customer service) for your assistance.

While at the dealership I spoke with the gentleman that helped me with the pinion seal replacement at 32k. I had him print out the work order, including all the materials used. Ends up that they didn't pull the cover and inspect the differential like I originally thought, so all they did was top off the oil with Ford "XY75W140QL". Since they didn't replace all of the oil, they didn't add any friction modifier, which he said was typical. Is it just me, or does this not make any sense? You make a solution of oil and FM, drain some out, add only oil - will the ratio of oil to FM be the same? I don't think so!

I am driving a lot next week for work and will be unable to get it back to the shop, so depending on how the phone calls go I decided to plan ahead and dropped the $6.62 on a bottle of XL3 which they had in stock. The oil they used and the XL3 check out according to the following lubrication specification document from Motorcraft.

https://www.fcsdchemicalsandlubricants.com/main/quickref/axlelube.pdf

Thanks again for the help everyone. Plans for now are to see what the dealer says Monday, but I'm betting that Monday night I'll be under my car in the garage (if not tomorrow).

 

[5LHO]

You can replace a pinion seal without pulling the cover if you're careful with your measurements of exposed pinion threads and pinion nut position. Filling with oil only could easily dilute the FM content to the point it makes noise, one the extant FM works its way out of the plates.

stupid *******, this thread boggles my mind. This is Ford and it's representatives at a dealer.

Thank you for acting on this by adding FM and potentially saving your trac-loc an ugly death. Based on what I've heard here so far, I wouldn't trust this dealer to wash the car much less perform any kind of maintenance or warranty work.