I plan on changing rear end fluid pretty soon, do I have to mix an additive with the oil? My dad say's I do, and I can only get it from the dealer.

 

only if you have the auburn posi, if you have the zexel torsion unit then you do not

 

I always used Mobil-1 gear oil, and added a tube of limited slip addative with it. Never bought anything from the dealership.

 

On the Torsen homepage they say GM requires the additive because some units have a little noise

 

That's strange, I always thought the additive was for the clutches in Eaton and Auburn limited slips.

 

The Eaton is a little forgiving and IIRC the newer ones (as in the past 8 years)with the carbon fiber clutches don't need the additive. But the Auburn needs only dealer additive, the parts store stuff in a tube does not work.

 

http://www.torsen.com/general/general_faq.htm

Is it true that the Torsen unit in the production Camaro needs the GM modifier added?

GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.

 

Some synthetic oils have the additive already in.
Like Royal Purple and Red Line... they already have the additive.

 

thats what i always thought

 

Mobil 1 also supposedldly has the additive in it

 

We don't have all your brands over here
The only rear end oil with additive I can find is what is used in BMW's and costs about $60 a gallon...

 

I've heard so too....

can someone here confrim or deny this???

 

You do have Silkolene (Fuchs), don't you?? Although I'm not sure what a gallon of that goes for over in the land of chocolate and perfect watches.

 

Sikolene? What's that?
US cars parts cost here 2-3 times more than in the States.

Perfect watches... for example?

 

How do I know if I have the Auburn and/or need an additive. There seems to be a lot of conflicting info on here.

 

If it's an 02 you have a Torsen.

 

Mine is a 98 M6.

 

It's an Auburn, as long as you know no one has ever changed it.

 

I have a 2002 Z28 some guy used 80-140 weght I thought the stock was 75-90 can I use the higher weght????? and skip the additive ????