Castrol SAF Carbon Modified SAE 75W/85

[ABomb369]

I am looking to see what if any info is available on this specialty gear oil. What makes it different?

I have been searching the web and haven't found much of anything. I can't even find this for sale or any PDS anywhere under the actual Castrol name.

This is the spec fluid for rear diff in the Holden Commodore/Chevy SS/Pontiac G8 based cars. I can find the dealer fluid (GM Part No. 92184900) which retails for about $40 a bottle.

I will be picking up a new 16 SS this week and I am already trying to nail down my fluids and maintenance schedule even though I don't have the car yet. I can be OCD like that.

Anyway would be really curious as to how this fluid is different and if there are any other products out their other than the OEM stuff.

 

[Kurt34556]

Check out the Castrol.co.au pages, they have it listed there.
It must be specific to Australia only.

 

[ABomb369]

I didn't even think to look there. However, did not find much as I don't see it listed under their standard products.

I did find this when I do a lookup on the 15-16 VF Commodore.

"Differential
Service Refill Capacity: 2.3 Litres. See note 823 below."

"823
Manufacturer recommends Holden differential oil Part No. 92184900 or Castrol SAF Carbon Mod. Refer to Dealer."

Must be an OEM specific fluid only. Still curious as to what makes the rear diff require this specific fluid.

My previous Pontiac GTO, also a Holden, took a 75W-140 in the rear diff. This seems really light.

It also has a service drain interval of every 45K miles versus the normal LLF that you usually see.

 

[MolaKule]

Originally Posted By: ABomb369


...Must be an OEM specific fluid only. Still curious as to what makes the rear diff require this specific fluid...



Is there any way to get an exploded view of this differential to determine what components would be so special?

Is this an LSD diffy?

Most 75W85 GL fluids are being used to get slightly higher fleet mpg's and are simply slightly lower viscosity fluids with the same GL-5 additive package.

 

[ABomb369]

I have confirmed it is an LSD and the MT version gets the 3.70 axle ration vs the standard 3.27 on the automatic.

I have not been able to locate an exploded view of the diff yet but I will keep looking.

 

[ABomb369]

I found this info from a 2015 Owner Manual.

Limited-Slip Rear Axle
Vehicles with a limited-slip rear axle
can give more traction on snow,
mud, ice, sand, or gravel. When
traction is low, this feature allows
the drive wheel with the most
traction to move the vehicle. The
limited-slip rear axle also gives the
driver enhanced control when
cornering hard or completing a
maneuver, such as a lane change.
For vehicles with limited slip
differential, driven under severe
conditions, the rear axle fluid should
be changed. See Track Driver Mode
on page 9-36 and Maintenance
Schedule on page 11-2.

Rear Axle
The rear axle fluid temperatures
may be higher than when driving in
severe conditions. Drain and refill
with new fluid after the first racing or
competitive driving event, and then
after every 24 hours of racing or
competitive driving.

Caution
During a first time track or racing
event, high rear axle
temperatures can occur. Damage
could be caused to the rear axle
and would not be covered by the
vehicle warranty. Do not drive as
long or as fast the first time the
vehicle is driven on the track or
raced.

For extended track use, GM
recommends installing a rear
differential cooler to protect the
rear axle.

 

[MolaKule]

Unless we find something unique about this diffy, this should work:

Redline LSD 75W85

Quote:
For extended track use, GM
recommends installing a rear
differential cooler to protect the
rear axle.


Excellent Advice

 

[ABomb369]

Thanks for the advice. I will take a look at Redline's 75W/85. I don't see any "Spec" requirement for the fluid. Just type and part number.

The whole "carbon modified" in the title of the fluid was throwing me off as maybe it was something different from a regular GL-5 gear lube.

 

[dailydriver]

Is this a clutch plate type diff (or Getrag viscous type?) in these, or some type of worm gear Torsen type?

8.5" ring gear?

That fluid DOES seem kind of thin, especially with all of the wear-in high temp warnings they give with that diff/r&p.

 

[ABomb369]

From what I have found from the SS/G8 forums they are a carbon clutch plate type.

I am just an arm chair mechanic so can't really comment on much more than that. I now how to drain and fill the fluid but wouldn't know where to begin on rebuilding one or know how it is put together.

On a side note:
How is that D4/MTL combo working in your T56? Thought about trying that combo in the TR6060 that I will have in the SS

 

[dailydriver]

Originally Posted By: ABomb369
How is that D4/MTL combo working in your T56? Thought about trying that combo in the TR6060 that I will have in the SS


It is going GREAT, no grinding, no big efforts to get into any gear, and no noise!

I am closing in on 200K miles on this gear box with NO rebuild, and I have NOT been easy on it either, although i do not try to 'speed shift' it with no clutch like some are known to do.

I would just use whatever they are suggesting in the manual for the 6060 UNTIL it is out of warranty, just to be safe, even though we know the D4, or the MTL (in hotter climes) would be just fine.

Unless you plan on heavily modding this car, in which case the warranty is out the window anyway.
EXAMPLE; are you going to remove and de-activate/'write out' from the tune the DOD/AFM feature on that LT1??
Add long tube headers?

 

[ABomb369]

Car will stay stock and I will use factory spec fluids until warranty is up. In this case the 6060 uses a D3 rated ATF or GM's re-branded fluid.

I am just thinking down the road when out of warranty and since this car won't see any action during the colder months I thought of maybe mixing in a thicker MTF in with the ATF. Plus, like you, plan on putting a lot of miles on this car and the tranny.

Quote:
EXAMPLE; are you going to remove and de-activate/'write out' from the tune the DOD/AFM feature on that LT1??


The SS/Commodore still uses the LS3 so no DI or AFM to worry about. I do take a hit in MPG and power compared to the LT1.

However, the stock tune of the LS3 in these seems to be spot on. Just powerfull enough to have fun but not so much your fighting the car. Makes for an extremely fun DD and why I bought one after test driving so many other cars.

What's not to like... V8, Rear Drive, Manual Tranny, and room for 3 kids in back!

 

[zeng]

Originally Posted By: ABomb369
From what I have found from the SS/G8 forums they are a carbon clutch plate type.


This carbon type friction discs has advantages over paper/cellulose/graphite type discs in withstanding higher surface temperatures.
In long haul express buses, it's prefered over sintered bronze friction discs which are noisy and harsh, thus is the most expensive among all.

Whilst the different clutch types above may possess different dynamic and static coefficients of friction, and by extension may require different types and proportions/concentrations of friction modifiers.
However IME, under a particular application, those differring clutch types all call for compliance to a particular industry standard without such differrentiations in oils as 'carbon modified' ;'cellulose modified'; 'graphite modified' or 'sintered bronze modified'.
Anyway, carbon type friction clutch discs is NOT proprietary to LSD's in SS but universal.

Just my $0.02

 

[MolaKule]

Originally Posted By: ABomb369
From what I have found from the SS/G8 forums they are a carbon clutch plate type.



But has anyone on these forums actually torn down a diffy of this type to confirm it?

And what exactly do we mean by, "carbon clutch plate type?"

The reason I ask this is that in formulating lubricants I often consult with the engineers of clutch material Manf. to determine composition, torque capacity, friction coefficients with various fluids, thermal transfer, etc.

As far as I can determine, there is no such thing as a pure "carbon" clutch material due to many reasons.

Most non-sintered and/or non-metallic clutch materials for car and light truck synchros' surfaces are made of a composite MIX of one or more of the following materials with an appropriate binder (a thermoset resin) and varies with Manf. (and not necessarily in order of % levels):

carbon (powdered or filament)
kevlar (aramid) filament
fiberglass filament
powdered copper
powdered aluminum
powdered manganese
silicon oxide

Just saying, we need to clarify when we discuss clutch materials.

 

[dailydriver]

Originally Posted By: ABomb369
The SS/Commodore still uses the LS3 so no DI or AFM to worry about.


Sorry, I did not look at your sig, and when you stated "16 SS" in the body of your post, I, for some reason, just took for granted you meant a 6th gen, '16 CAMARO SS.

But yes, IF I needed a larger 4 door sedan right now, I would take one of these over even a Caddy CTS-V, mainly because of NOT having to take the AOD/DOD and direct injection AND NO huffer in the valley to heat soak everything.

 

[dailydriver]

Originally Posted By: MolaKule
Originally Posted By: ABomb369
From what I have found from the SS/G8 forums they are a carbon clutch plate type.



But has anyone on these forums actually torn down a diffy of this type to confirm it?

And what exactly do we mean by, "carbon clutch plate type?"

The reason I ask this is that in formulating lubricants I often consult with the engineers of clutch material Manf. to determine composition, torque capacity, friction coefficients with various fluids, thermal transfer, etc.

As far as I can determine, there is no such thing as a pure "carbon" clutch material due to many reasons.

Most non-sintered and/or non-metallic clutch materials for car and light truck synchros' surfaces are made of a composite MIX of one or more of the following materials with an appropriate binder (a thermoset resin) and varies with Manf. (and not necessarily in order of % levels):

carbon (powdered or filament)
kevlar (aramid) filament
fiberglass filament
powdered copper
powdered aluminum
powdered manganese
silicon oxide

Just saying, we need to clarify when we discuss clutch materials.


I'm going to guess that it is a similar material/formulation as the carbon clutch pack plates in the current Eaton Posi.

Maybe they even sub-contract Eaton to build it for them??

 

[zeng]

Originally Posted By: dailydriver
I'm going to guess that it is a similar material/formulation as the carbon clutch pack plates in the current Eaton Posi.
Maybe they even sub-contract Eaton to build it for them??

+1

Your guess on materials being similar could, and should be right, at least by material specifications.
No. Eaton probably sources clutch discs, of whatever material types, from external specialist suppliers.

Quote:
The paramters of the various friction materials listed as following:
Bronze Material, Paper Material, Iron Material, Ceramic Material, Carbon,Material, Steel Mating Material
1, Bronze Material:bla,bla,bla.....
2. Paper Material: ..........
3, Iron Material: ............
4, Ceramic Material : ...........
5, Carbon Material:
It is high specific strength,high density,excellent thermal stability,close dynamic and static coefficient,wear resistant,very good oil compatibility.It is used for wet clutching and braking field which has high power load and pressure load,minimum allowed wear,and excellent durability,with applicance in rear axle differential,synchronizer of transmission in heavy vehicles,wet brake of heavy vehicles and military industry.Dynamic Coefficient (μd):0.07 - 0.10,Static Coefficient (μs):>= 0.10,Wear Rate (λ):J,power load: >= 60,000.
6, Steel Mating Material: .........................

http://www.brakefrictionmaterial.com/frictionmaterial.html