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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.
While I don't definitively KNOW the history, I bought it from the original owner whose wife and later their daughter, daily-drove the car for ten years. Never modded, no major repairs, miscellaneous repairs done at dealer, Dad did the oil changes. I feel certain that the car was not raced/tracked/hooned but also fairly likely that the diff fluid was NEVER changed.

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.
Thank you for the kudos!
 

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Mine started whining at around 35k miles. Whine turned into a slight growl. Took it into the dealership and they changed the fluid and when I picked it up the slight growl had grown from a slight growl to sounding like it was going to eat itself.

I inquired about the mechanic taking it for a spirited test drive and they said "no, we don't do that here.", umm ok.

Needless to say I threw a fit and they replaced it at their cost. They didn't know that I had ordered a new rear diff online and had it sitting in my garage (but it showed up damaged) so I sent it back and they gave me a refund.

Had a thread about it a few years back when it happened, sometime in '17 I think.

Here is what I learned from my research back then.

They are stout AF, until they are not.

Some of them fail with stock HP and some live with 1200.

There seemed to be no rhyme or reason to which ones fail and which ones don't.

The rear end is a known problem area.
 

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Two diff swaps for my car under warranty. One at about 10k due to making noise and the second was making noise and got it swapped the end of fall before the winter during which my warranty was gong to expire, don't recall the miles but it was tracked, I did get the over temp message and pull in each time it came on (car doesn't actually go into limp mode). The over temp message is way high, the oil is dead, and if you've seen it it is probably too late.

IMO everyone should put a cooler on. My thermostat controlled cooler turns the pump on after 30 minutes of driving at 80 on an 80 degree day. How much higher ambient are guys in TX seeing and how fast are they going for how long cooking the diff.
 

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To be fair, in my M8 car my axle bearings were done at around 80k miles and leaked fluid everywhere. The heat of DD highway miles I guess wore them out - i changed the diff fluid yearly.. alas,, no replacement parts and not rebuildable as the R&P were also showing wear. No idea why some live and others die?

I have a GForce unit that whines a little more with helical gears... but I like to beat the piss out of it with my 900+ ponies and so far, so good

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Did? I still drive it daily runs like new. I have used mobil 1 75-90 with gm additive. Also this car has several bolt ons.the
Thanks. I have a groaning coming from the rear when it's cold, and doing tight turns. Do you have anything like that? The noise goes away once it's warm.
 

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Thanks. I have a groaning coming from the rear when it's cold, and doing tight turns. Do you have anything like that? The noise goes away once it's warm.
That is likely from contamination in the clutches of the limited slip or not enough friction modifier. You don't need to change the diff to fix that. A fluid change should take care of it. Sometimes it takes a fluid change, some driving and a second fluid change. In that case you would see some improvement in the condition from the first fluid change and the second fluid change would help flush out enough of the contaminants that it would be ok.

I'd use this with the friction modifier already mixed in.
 

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I think i have a few quarts of rear diff fluid I can ship someone for $20.

$20 is $20...

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That is likely from contamination in the clutches of the limited slip or not enough friction modifier. You don't need to change the diff to fix that. A fluid change should take care of it. Sometimes it takes a fluid change, some driving and a second fluid change. In that case you would see some improvement in the condition from the first fluid change and the second fluid change would help flush out enough of the contaminants that it would be ok.

I'd use this with the friction modifier already mixed in.
Exchanged the fluid with that stuff a couple weeks ago actually; yet the noise remains. I will consider doing another fluid change if it continues after another couple of weeks.
 

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Exchanged the fluid with that stuff a couple weeks ago actually; yet the noise remains. I will consider doing another fluid change if it continues after another couple of weeks.
did you notice any improvement from the oil change you did?
 

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Yeah, these diffs are weird. My current one has 5 passes and about 3k on it, and is starting to make noises already.
Next stop GF 9in...
 

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I have determined that I will have to pull out the brand new diff I just installed for warranty replacement. It vibrates at higher speeds (even on the lift with wheels removed) and it has now started to make a low pitched roar. It had arrived with a significantly destroyed box and visible impact damage. I installed, hoping for the best.
I was disappointed.
At this moment I’m not certain when I will pull it but I WILL have to.


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