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Diff fluid?

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Old Oct 18, 2012 | 10:58 AM
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Default Diff fluid?

99 SS, How much diff fluid, what weight, and what kind is suggested? im sure it depends on if my diff is limited slip or standard in which case how do I find that out?
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Old Oct 18, 2012 | 12:50 PM
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If you have the original rear end still, then it would be a Torsen limited slip (you should see the RPO code "G80" on the SPID sticker). As it's an SS, I suppose someone could have originally ordered the car with the diff upgrade option from SLP. But chances are you have the stock rear, which calls for 1.75 quarts of 75w90 synthetic fluid with a bottle of GM LSD additive. Some people argue that the additive isn't needed on the '99+ rears, so that's up to you to decide.
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Old Oct 18, 2012 | 02:58 PM
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^ yup, I have read the same that some claim there is no need for the LSD additive, but for $4 or whatever it is, its cheap insurance. Some people also reported problems when not adding the LSD additive. Here is what I am running.
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Old Oct 18, 2012 | 05:02 PM
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The exact answers I was looking for. Thank you.
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Old Oct 23, 2012 | 04:29 PM
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I just did mine and put in Royal Purple synthetic. Royal Purple is really good stuff!
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Old Oct 28, 2012 | 10:01 PM
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Originally Posted by RPM WS6
If you have the original rear end still, then it would be a Torsen limited slip (you should see the RPO code "G80" on the SPID sticker). As it's an SS, I suppose someone could have originally ordered the car with the diff upgrade option from SLP. But chances are you have the stock rear, which calls for 1.75 quarts of 75w90 synthetic fluid with a bottle of GM LSD additive. Some people argue that the additive isn't needed on the '99+ rears, so that's up to you to decide.
Exactly to the T.
This is what i do when needed.
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Old Oct 28, 2012 | 10:13 PM
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The additive is just a friction modifier for the clutches in the auburn unit. Without it the clutches would never slip going around turns. With the torsen unit, there are no clutches to slip so there is absolutely no need for the additive.
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Old Oct 29, 2012 | 03:32 PM
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i prefer a paper gasket over silicone.......the silicone ALWAYS leaks for me
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Synthetic with no additive here and 200+ dragstrip passes and 11,000 miles.
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