24 GT MT Rear Differential Failing?

[tdbz24GT]

Had my Rear Differential and MT factory installed lubricants drained and replaced at 1,740 miles. MT looked clean but the Service Tech at my local shop (Not Ford) brought out a soda bottle half full of a nasty looking gray looking milky fluid. Pictured in the post. The tech who I trust said it looked like fluid out of a car with 100,000 mile not 1,740 miles. His theory is that the clutches in the rear end are bad and getting worse. Also the CV boot on the drivers left rear was leaking grease all over the chassis and wheel. I’ve got an appointment with my Ford dealer March 25. Never knew there were “clutches” in the rear end. Any thoughts on this?

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[Zig]

Rear gears will make mud while a leaking boot isn’t preferred

 

[tdbz24GT]

Thanks. I haven’t driven it hard yet. Will keep an ear out.

 

[Skye]

The CV boot failure is something which has been brought up before. Your S650 is not the first. Was the boot detached from where it is normally secured, or, was the boot itself cracked and broken? Any chance it was struck by road debris?

Regarding the diff fluid, I'd be concerned if there were metal shavings with that. The color, could be due to the surfaces of the clutch material seating and wearing in from new and general wear. The plates inside do rub against one another.

I'm attaching two files, explaining the differences between an LSD and Torsen; they each have their own advantages and shortfalls. It depends on how those diffs will be used, circuit track or drag race, for example.

Edit,

One thing you could do to monitor the diff: if a gauge to monitor is available ("axle", page 408 of the manual), watch the rear diff temp. Mine slowly comes up to temp and later stabilizes; it has never displayed a reading to give me concern.

If you are seeing a lot of slippage in the diff, I'd think it's show in two ways: 1) the driving experience, either in traction or sound, 2) the diff temps being much higher than expected.

 

[tdbz24GT]

Thanks for the information and especially the PDFs.

 

[Ryunker]

How do you drive the car? Hard? Any "track days"

 

[tdbz24GT]

I have not even done a burn out and have driven it like the old I am. Been on it a few times to around 5500 rpm but enjoy the handling since I put a Ford Performance Street Pak suspension on. In fact after that the GT actually handled better than my 2004 Porsche Boxster. So I sold the Boxster with 72,000 miles on it. But the V8 just feels right. So no I drive it without abusing it for certain.

 

[Dena]

Milky oil could be due to air mixing while you were driving. It would be best to let it sit over night and see of the milky appearance goes away. That said, my 96 mustang had a bad rear end from the factory. It would sing and took a while to verify it wasn't the transmission. When they assembled it, they didn't get the gears lined up and that caused it to sing. Ford rebuilt it under warranty and that corrected the problem. Gear lub used to be black but depending on where they put it, they can use something as thin as automatic transmission fluid I hope you guy is up to date on what ford is using because unless you race, you shouldn't need to touch the rear end for a long time.

 

[nickmallet]

i also had my cv boot on the drivers side come off not even 1000 kms. it took a month to fix
because a bolt was on back order and they damaged my rtr side skirt that i just installed. lol the inside of my door was scratched too.

 

[tdbz24GT]

Oops! Hate to hear that. Hope you get it resolved to your satisfaction. We’ll find out on mine on the 25th.

 

[Gr8ful]

My rear drivers side cv boot hole a small hole from the factory. A manufacturer defect. Grease everywhere. Dealer ordered a new one. Ford required the dealer to take pictures because the car only had 600 miles on it. The tech messed up the replacement. Broke the brake line bolt in the hub, just left it hanging lose, the link bolt half on and chipped the red off the Brembo caliper.
I had to correct all this myself, no way Im going let them touch it again.
This is why I don't trust dealer service departments.

 

[tdbz24GT]

I hear you loud and clear. No one wants to work- they just want a job getting paid. You’re not alone. For every one story like yours there are many more. Man I feel for you. Assuming you have records and some proof I’d be on social media or better yet call Ford. You paid good money for your car and get shafted by the dealer. HQ Ford may be the best choice.

 

[tdbz24GT]

UPDATE
Took the sample factory rear differential fluid to the dealer and was advised that the clutches in the differential have a coating on them and during break in clutch material in the fluid normal. Regardless I had the service manager look at it and he agreed but he would document my concern. Secondly the “CV boot” was not my problem at all. The drivers side half shaft was bad and required replacing. All under warranty. My only complaint is they left greasy hand prints on my drivers door and hood. I guess all things considered it’s a win.

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