[wesmanV]

I've got a '12 V with about 85k on the clock. I've had a bit of a whine from the rear end for literally 50k miles.....didn't think it was that big of a deal and the dealership never mentioned it until about 20k miles ago at an oil change. ( Of course they didn't mention it when it would have been under warranty)

It seem it finally sh!t the bed the other night. Anyone else have their rear end go out? If so, what did you do? Replace with stock? Rebuild it? Replace with aftermarket??

Thanks for any info provided.

--wes

 

[SoCalDave]

My 2011 sedan with 95k on it had started to whine when I bought it about a year ago. Couple of months ago it got worse so having an extended warranty I opted for when I bought it I dropped it off at the Dealer to investigate. Called me that afternoon stating there was metal flake in the oil and they contacted my warranty claim which was approved. New rear-end in now.
I've always heard the two biggest weak links to this platform are the SC spring loaded isolator and the rear-end.
Both mine are new now at just over 100k miles.

 

[Karch]

Neither are weak links, but they can make noise.

The rearends are stout AF


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[papi]

^^ Yea, what he said.

 

[MrSurly]

The differentials are a known issue.
You might not care for the term “weak link” because they ARE stout AF, as far as breakage, but the fact remains that they ARE a known failure point in as far as “whining like a bitch” and “howling like a wolf” are failures.

My own “stout as fuck” differential just set me back two thousand bucks, which I thought was pretty stout.

As far as repair options, the only direct replacement option is replacement with a new unit from GM.
The GM unit is 2500 from the dealer, carry out. Rock auto is just under two grand for the same GM part.

Rebuild parts are simply not available.
Bearings, yes, gear set, no.
There is a very thorough thread somewhere here by walkers4x4 detailing his efforts to rebuild; his effort was grand, he endeavored to persevere, but was ultimately unsuccessful.

Aftermarket solutions exist (Creative Steel) that are custom cases housing Ford Nine Inch gear sets.
These are the ultimate fix if you are planning to do a serious track car.
They start around five grand.

For my application I elected to replace with the new GM unit from Rock Auto
and install myself. I then added a cooler to hopefully prevent a reoccurrence.


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[Karch]

Well, I have seen well in excess of 1200 rwhp through them without failure. Some do whine. Do you know the history of yours?

When you buy a used car you don’t know the entire history, generally.

And, fwiw, 1200 rwhp is about 2.5x the stock power, so I would say it’s very stout.


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[MrSurly]

You’ll note, when doing a thorough review of my post, ~I know you will review it~ that I am in agreement that they are stout. They are strong. They are invincible. They are wom... wait. OK, they don’t break. However, one of their prescribed performance parameters is to be silent in the performance of their duties. This is a performance requirement of EVERY automotive differential. The mere continued success of one function (even excelling at that function) does not put at abeyance the requirement that the other functions be performed as well. The parsing of the phrase “weak link” to center upon the structural implications of “weak” is thoroughly pedantic and I’ll congratulate you on going there.


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[MrSurly]

I don’t know the history of my car. That doesn’t alter the fact that the whining differential issue is thoroughly known, chronicled, posted about, documented and has even spawned an industry of aftermarket workarounds.
I was aware of the diff whine issue before I went shopping for a V.
I learned about it here as well as a hundred other places that Google will readily provide.
Known issues, especially those that are expensive to address, are commonly referred to as “weak links”.


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[bucky502]

3rd rear replaced for whine in 3 years. Now that it's modded no more warranty. Replaced with thicker synthetic Mobile 1 gear oil that helped some......

 

[ThunderOne]

The differentials are a known issue.
You might not care for the term “weak link” because they ARE stout AF, as far as breakage, but the fact remains that they ARE a known failure point in as far as “whining like a bitch” and “howling like a wolf” are failures.

My own “stout as fuck” differential just set me back two thousand bucks, which I thought was pretty stout.

As far as repair options, the only direct replacement option is replacement with a new unit from GM.
The GM unit is 2500 from the dealer, carry out. Rock auto is just under two grand for the same GM part.

Rebuild parts are simply not available.
Bearings, yes, gear set, no.
There is a very thorough thread somewhere here by walkers4x4 detailing his efforts to rebuild; his effort was grand, he endeavored to persevere, but was ultimately unsuccessful.

Aftermarket solutions exist (Creative Steel) that are custom cases housing Ford Nine Inch gear sets.
These are the ultimate fix if you are planning to do a serious track car.
They start around five grand.

For my application I elected to replace with the new GM unit from Rock Auto
and install myself. I then added a cooler to hopefully prevent a reoccurrence.


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is the unit a complete third member or is it the entire rear end?

 

[MrSurly]

is the unit a complete third member or is it the entire rear end?

um...yes?
It is the 'entire' differential assembly which is not serviced with a removable 'pumpkin' or third member. It is the entire differential housing and its contents.
It's not really green but this is Rock Auto's picture

 

[ThunderOne]

um...yes?
It is the 'entire' differential assembly which (because it's an IRS unit) is not serviced with a removable 'pumpkin' or third member. It is the entire differential housing and its contents.
It's not really green but this is Rock Auto's picture
View attachment 149451

Yeah I realized the stupidity of my question later lol. Since it's a whole unit, I don't imagine that being too difficult to swap out

 

[MrSurly]

3rd rear replaced for whine in 3 years. Now that it's modded no more warranty. Replaced with thicker synthetic Mobile 1 gear oil that helped some......

Have you added a cooler? I've been told that a cooler saves the rear end by preventing overheating. They're all the rage these days.

 

[ThunderOne]

Have you added a cooler? I've been told that a cooler saves the rear end by preventing overheating. They're all the rage these days.

I have not, I just bought my car a month ago so I've been slowly working my way around the car with a fine-tooth comb. The car has 38k miles on it and I just replaced the diff oil as a preventative measure. I haven't looked into diff coolers yet though.

 

[MrSurly]

Has anyone installed this diff cooler?

LOL, this is not what I was looking for but it speaks volumes about the diff issues on these https://bobistheoilguy.com/forums/threads/acdelco-75w-90-syn-axle-lube-13-7k-mi-oci-34k-mi.253987/

www.ctsvowners.com

 

[Karch]

I guess it’s one’s interpretation of a weak link, then, especially if you know the history of the V1 and those catastrophic failures compared to the V2 and whining.


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[ThunderOne]

Has anyone installed this diff cooler?

LOL, this is not what I was looking for but it speaks volumes about the diff issues on these https://bobistheoilguy.com/forums/threads/acdelco-75w-90-syn-axle-lube-13-7k-mi-oci-34k-mi.253987/

www.ctsvowners.com

hmm, I guess I should consider going up to a heavier weight oil huh? After reading that BITOG thread it seems like 75-90 isn't cushiony enough for the diff

 

[BV_Mully]

FWIW I've tracked my car without a diff cooler and had zero issues. My car has 76k miles on it and the first known diff fluid change was at 74k miles just before my track day. Road course work is where they are known to overheat and put the car into limp mode, but I had no such issues. I will add a diff cooler since I plan on doing the bigger tracks (Buttonwillow, Streets, Chuckwalla, etc.).

Remember that people are far more likely to post about issues that successes. The diff issues with the V1 are well documented, but V2 diff issues are few and far between.

 

[MrSurly]

It's clearly true that the V1 differentials have a history of catastrophic mechanical failure... they are known to rupture the case, spilling expensive bits all around.
The V2 diffs don't share the case ruptures or other high drama as first notice, but the whine isn't without import; whining is a direct indication of a failure mode, as affirmed by GM. If not addressed and continued in service, drama will eventually follow as gears chip and bearings crumble. How long will it take? No idea. But you can rest assured that IF the whine was NOT a failure indication, GM would not have warranted them based on the noise or stated so in the TSB. Take a look at the linked post above to see the inside of my whining diff. How much longer do you think it would have gone, given the condition of the bearings? Could you look at the pics and assess it as "no failure here, it's just a noise...they all do that. Bolt 'er back in there, boys"?
Lack of dramatic diff explosions does not mean there's nothing to see, here.

If it's WHINING.... it IS broken.

 

[BV_Mully]

...How long will it take? No idea...

...I've had a bit of a whine from the rear end for literally 50k miles...

50k miles before the whine manifested into a failure.

@MrSurly your diff certainly had seen better days, but most Vs with a history of consistent diff fluid changes rarely have issues. If you car was driven like a raped ape for 100k miles without any fluid changes, I would expect the inside to look similar to yours.

BTW, I'm going to use your diff cooler thread as a guide when I build mine. It's well documented and my hat it off to you, sir.