Diff fluid?
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Teching In
Joined: Oct 2012
Posts: 19
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From: Fort Worth, TX
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?
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
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.
^ 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.
Staging Lane
Joined: May 2012
Posts: 50
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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.
This is what i do when needed.
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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