LS1T56FTW

iTrader: (3)

As you can see in my sig, I have a 99 Z28, do I have the Auburn, or the Torsen differential? Also, I want to change the fluid in it, and in the owners manual it says to use SAE 75W-90 for the fluid, do I need to put an additive as well into there (Depends on what diff type I have)? Thanks.

Bob@BruteSpeed

iTrader: (16)

I'd put the additive in it. Even if the differential doesn't need the additive, it won't hurt anything. Bob

bww3588

iTrader: (49)

you have the Torsen LSD, (should have anyways) and it does not require the additive. the additive is a friction modifier which makes the clutches in an Auburn type LSD slip so it doesnt destroy them when turning. the Torsen has no clutches to slip, so an additive is pointless, but as Bob said, it wont hurt anything.

Snake_Skinner

iTrader: (12)

What is this additive exactly and where can i buy it?
and what years did they use Torsen vs the Asuburn LSD's?(like is there an RPO code i can look at to tell)

bww3588

iTrader: (49)

99+ had the Torsen, and no need for the additive

some SS's and firehawks got the Auburn from SLP, but not sure how to check other than pulling the diff cover.

the additive can be had at any autoparts store, usually its around the gear lube, but check because some gear lubes already come with the additive.

ss346ci

Yes if you can list your RPO codes i can check and see which you have. I have a 2000 SS and i have an auburn with clutches which does require the additive. The additive can be had at autozone or o'reillys. You can pull your cover and check visually to be sure. If you see thin disks that look like auto tranny clutches then you need the additive. I recommend mobil 1 75-90 and the gm additive...

bww3588

iTrader: (49)

just out of curiousity, how is an RPO going to tell you which diff you have? all it tells you is if you have a LSD or not. G80...

Snake_Skinner

iTrader: (12)

99 and up thx bww3588 thats what i was looking for! Also was LSD not everything they offered or could you get something else, i mean what would the RPO code say besides LSD??

bww3588

iTrader: (49)

some people can look up the VIN and tell you what SLP options a certian SS or Firehawk had, but the RPO sticker wont tell you wether it had the Auburn or Torsen. if you have the WS6 in your sig, its got eh Torsen, and doesnt require the addative. however...it cant hurt to put it in. some people have put it in and noticed a quiter acting diff.

personally, i would put it in regardless, its better to have it when you dont need it, than not have it when you do.

01ssreda4

iTrader: (96)

https://ls1tech.com/forums/gears-axl...-searched.html

ss346ci

At risk of admitting to a huge mistake here I have the auburn and used syntec 75-90. Did I hurt my diff or do irreparable damage to my gearset? Can it be fixed by switching back to dino lube?