When I install it should I use the limited slip additive?Someone at another board told me NOT to use it cause it caused there's to slip & act like a one-legger.Anyone use or not use?Thanks
BD3

 

you do not need to use the additive since this is not a clutch type posi

 

Ditto

 

If this is a locker rear end like a Detroit Locker, Then I would not worry about adding the posi additive. I have a non clutch type locking rear end under my 87 T/A and do not use the additive.

 

A Torsen is not a locker, it's uses worm gears to transfer torque from the slipping side to the other. A standard Torsen can peg-leg like an open diff if the slipping side loses all traction (like on ice or if the tire is lifted off the ground).

You don't need to use limited slip additive with a trosen, but GM does to prevent gear noise.

 

Ditto? Ever read the Service Manual? I have and it clearly states to use the additive.

 

So what's the final verdict??? My posi goes in on Tuesday.

 

Really? What model year car's service manual are you referencing?

 

I've been running an HD Torsen for three years now, no additive. I ran plain Valvoline 85W-90 lube in it for the first two years, just switched to RedLine shockproof heavy lube w/ the gear change. No noise and no problems, no wear on the Torsen's internals when we pulled it to swap gears.

 

Just to close this one out, if you're referencing any factory service manuals and applying this to a Torsen you're wrong. The Torsen was installed after assembly in SLP-modified 4th gens.

So...if you're reading anything other than a manual for SLP-modified 4th gens this doesn't apply.

Marc 85Z28, you taking shots at GMTech is like a Poodle barking at a Rottweiler.

 

If you don't know what you are talking about, please don't prove your ignorance.

ALL LS1's received the Torsen, stock, from the factory. The Auburn unit was the only optional diff from SLP.

 

Well let's put it this way. . . if I did throw in a bottle of Posi additive, WOULD IT HURT ANYTHING???

And secondly, how many bottles of 85W-90 should I give the guys at the shop? Basically I'm supplying all the parts and they're just doing the labor.

Thanks guys,

-The Gunny

 

First things first. The Service Manual calls for 75W-90 synthetic, not 85W-90. You will need 2 bottles. AND it also calls for the limited slip additive. You can go by what a few uninformed people here suggest, or what GM recommends.

 

gmtech may or may not be a certified GM mechanic.

If the manual calls for additive in the late 4th gens with a torsen, i would chalk it up to holdover language from the old documentation and / or to cover the possibility that there was a clutch type posi installed for whatever reason (SLP, leftover parts, etc)

Posi additive is a friction modifier to help clutches slip against each other more smoothly. Ever leave additive out of a clutch type posit rear? Notice how it tends to bind more.

Now as stated, a torsen DOES NOT have a single clutch in it. So why it would require a friction modifier is beyond me. It won't hurt it, but it sure doesn't do anything either.

So, if the question is, what do i believe, a gm service manual, or simple logic, well logic rules the day for me. GM service manuals also recommend 100k mile plug change intervals and the smallest oil filters made for applications. They are not gospel.

 

Don't get your panties in a jam dude. Granted you're right about the non-SLP cars having the xexel, but I can thumb through my GM manuals and find plenty of mistakes, so just because it's in there doesn't always make it right.

Since some of the cars (i.e. SLP cars) had the auburn, I'm sure it was easier for the manual to just keep it simple and say to add it to all of them. It's not going to hurt anything in the Zexel, and GM gets to make a few more bucks on unecessary parts.

 

Holy Cr@p! What a bunch of whiners. Damn, Auburn does not have a single clutch in it but still recommends using a friction modifier. The friction level in the differential determines the torque bias between the gear assemblies. I.E. changing lubes will change the holding power of your limited slip differential. Too high a friction level will cause a popping, yes even with non-clutch type differentials. By modifying the friction properties of standard differential lube with an additive, the wear properties and torque bias of a differential can be maintained at the MANUFACTURERS recommended levels. I mean how would an arrogant company like GM know what to use? GM just speced out the differential, lube requirements, and had someone make it to fit their cars. (sarcasm) After all "common sense rules".

Check this link to Torsens' own website and you will see that even Torsen recommends a lube additive!

http://www.torsen.com/general/genera...rential%20work

 

Umm.. auburn does so have clutches.. theyre just cone shaped instead of plates.

 

This why I added it btw-->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.
BD3

 

Just as a data point, I recently went to RedLine "shockproof" heavy gear lube and no noise w/ my Torsen. Darn Richmond gears are kinda whiny, but that's it.

 

Right, like i said, it doesn't *need* the additive as they clearly state right here. Thanks for the reference to back up what i was saying.

 

It will not hurt anything in a Torsen differential to add posi additive.


don't capitalize ALL.

1998 LS1 f-bodies received the Auburn type posi stock, from the factory. The upgrade was the Torsen.

1999 - 2002 LS1 f-bodies received the Torsen T-2, and the upgrade was the Auburn.

You've some Ritalin to take.


Cones or plates, they're still considered clutches.

 

I do not consider the metal-to-metal interface of an Auburn to be a clutch, more of an interference fit. By clutches I mean renewable friction materials. The Auburn is not renewable!

BTW, "need" oh you don't need to take the advice of GM just understand that they have alot more experience with these differentials than any of will have in a lifetime! If GM recommends using a lube additive then it would be essential to me. I.E. (I suppose you don't need to run premium fuel in a high performance engine but why would you kick yourself in the nads.) Not running a lube additive would just be sacrificing a possible benefit!

 

Maybe the Torsen was optional over the Auburn in the regular Z28 in 98?

I know the 98SS brochure that I have states the Auburn Pro as an option over the Torsen for $699.99

 

You're not taking Z28s into account. In 1998 Z28 got an Auburn type with a Torsen optional. An SS got a torsen with a HD Auburn available as an option.

Once again, don't capitalize ALL.


As soon as the 98 SS brochure encompasses ALL LS1s, sure.

I post a little bit on LS1.com

edit: Nice edit of your post.

 

K.. so an eaton with steel clutch plates installed, instead of the carbons, doesnt have a clutch anymore right?

 

:sillylol: @ this post....... for goodness sake

 

What kind of posi comes in the lt1 year camaros like the 93-97