cgormanZ28

Alright fellas here are a couple of questions - from what I've read on GM-SI,
the differential fluid for my 2002 Z28 Camaro is requiring a GM Friction
Modifier. I'm a Maserati technician and our friction modifier is very
precisely measured, does the GM differential require a certain amout of
friction modifier as well? Also, instead of using the standard ACDelco diff
fluid can I use a replacement such as Royal Purple w/friction modifier?
Anyone using Royal Purple and experiencing issues? The reason I want
to use RP is because I can get it at work for nothing. Any advice or knowledge
about it will be appreciated. Thank you.

mjs1012

iTrader: (36)

Your 02 rear should have a Torsen unit so you don't need to put the additive in like you would for an Auburn Unit. I personally use regular 80w90 non-synthetic fluid and haven't had any issues.

cgormanZ28

Thanks MJS. What is the Auburn and Tore units differences? I have a 10 bolt 7.5" right, not 7.625"?

demonspeed

iTrader: (7)

Auburn was a clutch-style limited slip in which case one should not use limited slip additive nor synthetic gear oil. The Torsen T2 is a worm-style limited slip that suggests the use of synthetic gear oil without the need for friction modifier; however, one can use conventional gear oil with the Torsen so long as friction modifier is used as well.

You can read more here: Torsen T-2 specifications

If you've got an '02 then you've got a Torsen, so I'm curious what you're reading that states the friction modifier is required.

cgormanZ28

Thanks for the information guys!! When I was at UTI I remember reading in the
GM Service Information sheets about the friction modifier for 10 Bolt 7.5"
rear ends with or w/o the 7 5/8" or 7 1/2" ring gears. Its been a few years
since school, so my memory could be very wrong.haha.
Any kind of identification numbers used, for finding whether a rear end is
Torsen or Auburn??? RPO codes or anything?? Thanks for the information.

demonspeed

iTrader: (7)

Ah, ok. That makes sense

99-02 had Torsen T2 from stock.

However, one could get the Auburn from SLP via RPO "Y2Y" on their Firehawk or SS. This is rare, though. You can look on the driver door at the SLP sticker which lists any "second-sticker" upfitter content. The caveat is many of those stickers faded. If you would run into that, just contact SLP with the VIN and they can verify. They also have this website for that purpose as well: http://www.slpcamaro.com/

Here's what it would look like/say if it had the Auburn (and other options):