So much conflicting Diff Fluid info in here

[Rock-It Man]

Originally Posted by Russell James

The most simple way I can explain it:

Read the owner's manual. Read the bottle of gear lube you chose to use.

If you chose the GM lube, you need to add the GM LS additive. This is because that same lube is also used in G80 truck locker diffs with no LS clutch plates. If the diff has no LS clutches, and is a locker type, the LS additive is not needed. The Camaro uses a clutch type LS diff = needs the LS lube additive.

If you chose another brand of gear lube, read the bottle. If it says - "contains limited slip additive" - then you don't need to add anything.

I used one qt of RP Max Gear 75w90. Says right on the side of the bottle "contains limited slip additive". Done. Changed it two years ago, diff still working perfectly. One qt, not two.

I trust the Amsoil gear lube and their additive will also work perfect.

Whether or not you have to add the LS stuff just depends how the gear lube was packaged. Some companies prefer to have a synthetic gear lube without the LS additive, so it can be used in non LS applications like a locker. Then you just add their additive if you do have LS clutches. Some companies package it already included. 6 of one, half dozen of the other.

Great explanation.

[Nessal]

Why not just use the GM stuff?

[NavyDood]

Originally Posted by Nessal

Why not just use the GM stuff?

Because you pay grossly over inflated prices buying from the dealer and you get nothing more than a Group III synthetic. You can get Mobil 1 for much less. Or you can get a real synthetic like a Group IV or Group V which will be superior in all aspects and it will cost you less also.

[CruznSS]

Used RP (royal purple) for mine with no issues.

CRUZN-SS VIA tapatalk

[clg_98ta]

Originally Posted by CruznSS

Used RP (royal purple) for mine with no issues.

Same here... 1 quart of RP, didn't quite take the whole quart. Diff is quiet and I did not add any slip additive.

[Doc]

I use Royal Purple in both diff and trans. Use RP's MaxGear 75w90 for the diff, and Synchromax in the trans if you have the manual trans... yes I know it's an automatic fluid but that's what GM says you use in the Camaro's manual trans. You'll notice the reduction in noise too. Good stuff!

[MIKnam67]

Originally Posted by Andy@AMSOIL

That is not true,, just because bottle says no need to add friction mod you don't have to add,,, you may need the friction mod all gifts don't react the same,, in theory they should

Royal Purple says you DO NOT add friction modifier or anything else to the Royal Purple Max Gear for Limited slip Diffs in our Camaro's. It is built in with their product. If you have a question call them'

I sent email to RP Tech Dept Here is reply;
2010-2012 SS Camaro
Auto Trans - RP Max ATF Part # 01320
Manual 6sp Trans. - RP Synchromax Part # 01512
DIFFERENTIAL - RP Max Gear 75W-90 part #01300 NO ADITIONAL limited slip friction modifier needed
PER ROYAL PURPLE TECH DEPT.

[Badbubba]

Originally Posted by Andy@AMSOIL

Get 2 qts of severe gear 75w90 with 1 tube of friction mod additive all shipped for 38.98
And call it a day

Andy, are you stating that the amsoil needs ls additive or do I try it without the ls additive and see what happens. If it chatters, add some. The reason I'm asking is bc you posted on another thread http://www.camaro5.com/forums/showth...29#post4370229 , post #9, that severe gear 75w90 contains ls additive. Do I add more? Will more/too much diminish the locking ability of the diff? I don't want to take a shot in the dark at it or lay under the car repeatedly until I get the recipe correct. Could some of the 1 wheel burnouts be caused by having too much additive. Yes, I do understand every car is different, but I need to have a good starting point. I'm leaning toward amsoil, familiar with the offroad products, but with members posting all they had to do with royal purple was to dump it in and go, then rp is a viable option. I know I'm confused, but am I really confused?

[OBSSEST]

Yes, I agree that this issue is as clear as mud.

I'm not real big on the "try it and see if it makes noise" approach. The whole purpose of these gear oils with the LS additive already included is for convenience. But with all this guess work the convenience is eliminated. So, why isn't there enough LS additive already in these products so that we don't need to add any more?

I'm guessing that Amsoil, Royal Purple, and others, add just enough LS additive to their products so that it works with most applications. Their ratio isn't necessarily ideal for the Camaro rear end.

I think there are probably alot of people who have added too much and are suffering from one wheel burnouts due to too much slippage. They just don't realize it and maybe don't care either.

[Redemption]

I will play devils advocate.... I ran royal purple for 2 weeks. (changed at 1000 mile mark)

I had more groaning, clunking, horrible racket than an old diesel truck pulling an rv.

Switched to mobile 1 with GM additive, not 1 peep since.

My 2 cents.

J


Sent from my payphone using carrier pigeons.

[DoubleARS]

Originally Posted by OBSSEST

Yes, I agree that this issue is as clear as mud.

I'm not real big on the "try it and see if it makes noise" approach. The whole purpose of these gear oils with the LS additive already included is for convenience. But with all this guess work the convenience is eliminated. So, why isn't there enough LS additive already in these products so that we don't need to add any more?

I'm guessing that Amsoil, Royal Purple, and others, add just enough LS additive to their products so that it works with most applications. Their ratio isn't necessarily ideal for the Camaro rear end.

I think there are probably alot of people who have added too much and are suffering from one wheel burnouts due to too much slippage. They just don't realize it and maybe don't care either.

I too am confused. I just ordered the GM branded oil and modifier from gmpartshouse.com to be done with it.

[OBSSEST]

Originally Posted by DoubleARS

I too am confused. I just ordered the GM branded oil and modifier from gmpartshouse.com to be done with it.

You don't have the parts numbers for these do you? I just tried to look them up but got lost in their parts catalog, couldn't find fluids listed anywhere.

[DoubleARS]

Originally Posted by OBSSEST

You don't have the parts numbers for these do you? I just tried to look them up but got lost in their parts catalog, couldn't find fluids listed anywhere.

Here you go!

Synthetic Axle Lubricant - 89021677
Friction Modifier - 1052358

Right from the owners manual.

[OBSSEST]

My dealership sells ACDelco 75 90 synthetic gear oil. Is that the GM stuff?

I checked out my rear diff today anticipating doing this job. I found that my exhaust pipe is too close to the drain plug to get a regular 3/8" socket on there. I have a Solo catback and even after removing the hangers I couldn't move it enough to get my tool on there.

I am going to need to get a low profile breaker or something. I never checked this out with the stock exhaust so I'm not sure how much room there was before.

It seems like every little job requires me to buy some tool I don't have. sheesh