Gear Oil Discussion for ARB lockers

[Romer]

In another thread it was pointed out I should be using 85 to 140wt in my differentials that have ARB lockers instead of the 90 wt I was using. While researching this I found suggestions not to get Gear Oil for Limited slips as they have additives that are bad for the ARB seals. Not sure if that is true

I like using Synthetic

I was then researching between Mobil1, Vavoline, Royal Purple and Red Line. Lots of people came on and said Amsoil was the best. Others came on and said each of the others is best. In no case was clear proof given other than test results provided by the company they were praising .

Synthetic seems to come in 75-140wt

So, looking for data on the following

1. Is the LS part harmful to the seals?
2. Is there any data to really support in this application one brand over the other? I am guessing they are all good with small variations in the makeup

This is the one I wanted to get before I read about the friction reducers as part of the LS only because it's what I have used for years and never had an issue

Then there is Red line

Valvoline Full Synth picture shows 75-90, looking at 75-140

Royal Purple

and Amsoil Severe Gear

Feel free to add other questions you have on Gear Oil

 

[grinchy]

To be clear do you have gears and lockers, or just lockers?

 

[Romer]

How can you have a diff that doesn't have gears? Gears and lockers

 

[Fisher23]

If it meets the certification .. then it's likely fine. I generally use mobile-1 as they tend to "supply" the dealer oils.

I worked in a liquid package company when I was young .. and the same train car of oil was used for many manufacture/dealer oils .. just in a different package.

 

[grinchy]

How can you have a diff that doesn't have gears? Gears and lockers

Stock or aftermarket gears

 

[tirewater]

As long as you use the proper weight and specification, does brand really matter? Has there been a differential failure due to non-named brand gear oil being used? I certainly *feel* better using a premium brand, but deep inside I don't think it makes that big of difference for everyday use.

Arb lists GL-5 or MT-1 weights based on usage (90wt or 140wt). With industrial/heavy recreational being 140wt.

https://www.arb.com.au/assets/air-lockers/6-01.pdf

Seals are either Viton or Nitrile. I did not find any documentation on LSD additives in regards to what they are, but I imagine seals would hold up fine.

https://www.arb.com.au/assets/air-lockers/6-09.pdf

The Mobil LS gear oil you listed has this in their webpage:

Compatible with typical automotive seals and gaskets

• Helps to minimize leakage and reduce contamination

 

[Romer]

Stock or aftermarket gears

are you just increasing posts? stock or aftermarket do no matter towards gear oil

 

[Romer]

As long as you use the proper weight and specification, does brand really matter? Has there been a differential failure due to non-named brand gear oil being used? I certainly *feel* better using a premium brand, but deep inside I don't think it makes that big of difference for everyday use.

Arb lists GL-5 or MT-1 weights based on usage (90wt or 140wt). With industrial/heavy recreational being 140wt.

https://www.arb.com.au/assets/air-lockers/6-01.pdf

Seals are either Viton or Nitrile. I did not find any documentation on LSD additives in regards to what they are, but I imagine seals would hold up fine.

https://www.arb.com.au/assets/air-lockers/6-09.pdf

The Mobil LS gear oil you listed has this in their webpage:

Compatible with typical automotive seals and gaskets

• Helps to minimize leakage and reduce contamination

This is where I was at. There is a lot of conflicting information on the web. Thought it worthy of a discussion here though

 

[LINUS]

I hate to muddy the waters even more, but the simple answer I know from being an operator in a oil refinery (I was light ends - nonene, propane, butane to keep it simple) — but I knew the heavy ends units/end products & all the brands of oils were distilled from the same unit, the differences being the additives we were shipped in bulk totes to add prior to trucks leaving the refinery.

Without getting all geeky, I can say I’m a firm believer in Chevron & Techron bottles as my fuel, and use Mobil 1 in the motor.

The decision in the transfer case & diffs used to be either Mobil 1 or Royal Purple between all us refinery guys, but alot of guys were starting to go Amsoil & I finally used in my ARB’s in the old LX450 is Amsoil.
IDK if there are different flavors of Amsoil, I get & alot of us use one that is normal pale yellow in a clear bottle.

What really sold me on the Amsoil:
I had a ‘problem child’ keeping the seals from going out way too often in my front ARB (the 2 red o-rings that aren’t supposed to puke gear oil), and I finally had quit Mobil 1 & went Amsoil for my final R&R job on that locker, and it still was fine & not puking any mist the day I sold that 80.
I bought the LX450 with the lockers installed, but it was that 3rd R&R of the seals that fixed it, and I checked the seal housing each time almost expecting to find a burr, etc - nothing.
Not even the o-rings had any odd marks, and in reality the FR wasn’t used nearly like the RR, so I was eating seals inbetween maybe 10-15ish - cycles of the locker (easily 2/3 of those were just in my yard exercising them). It was frustrating.

Was it the Amsoil? IDK - but when I do either Harrop or ARB my RR Tundra diff I’m going Amsoil again.

IDK if that helps or makes things worse - it’s just my experience.

 

[Romer]

Experience is a awesome. Thanks for your input

 

[JohnJB]

We like muddying the waters here, so that's okay

I mentioned in the other thread but many of the folks I know who use their lockers the most and under the most severe use (rock buggies) have switched to el cheapo Super Tech stuff from Wally World. It's GL5 spec. The caveat being these are the types of folks who change their diffs at least once a year if not twice. This being the main reason for the switch as they can pick up Super Tech for less than half the cost of Mobil1 counterpart.

Me? I've started to drink the Amsoil KoolAid. Granted no lockers in the 200 right now. I used Mobil1 in the old Disco with ARBs and those units had been in the truck for nearly a decade and 70k miles (mostly PO miles). Never an issue for me and I'd fire them regularly just to make sure everything was working (cus when you own a Rover, you live in constant fear of it breaking ).

 

[SchobTime]

How can you have a diff that doesn't have gears? Gears and lockers

what is a gear locker? and why does it need oil?

 

[Fisher23]

what is a gear locker? and why does it need oil?

I think they were thinking with aftermarket gears you might need a different oil.....

 

[navydivedoc]

To Muddy the waters further...I have dynatrac prorock 60s in my Jeep LJ. They specifically recommend a dino oil over synthetic. Testing they did found the axles ran hotter with the synthetic. They also specify either 80-90wt in mild climates, or 80-140 in hot, even with the ARB which I have front and rear. For my use case, where it gets a ton of offroad use, dusty, water crossings, etc I just use walmart Supertech GL5. Cheap, meets standards, and mine get at least an annual change, and more if I've done a bunch of water crossings on any given trip. That's with the PITA of having to pull the diff covers. Assuming you are using yours as designed with the ARBs, I would personally just use the cheap dino oil and change it as above. Doesn't get much easier than the LC diffs.

Edit to add: In my LC, daily driver road warrior, and maybe tow vehicle but no serious offroad use, where I won't change the diff fluid frequently, I will use Redline 75w85 synthetic.

 

[Romer]

what is a gear locker? and why does it need oil?

I was discussing Gear Oil for the diff that had a locker. The diff has to also have gears to make the wheels turn The gears are outside the locker but within the diff. Not sure what the person who asked the ? thought. It didnt make sense to me

 

[Romer]

I am sure any of these gear oils would be fine. I have run Mobil 1 in all my rigs for years and never had an issue. Although I havent owned the same rig for over 10 years.

I did find lots of mentions of Friction modifiers are bad for ARB o rings. One was a post from an offroad site who called and they said LS is probably OK just stay away from high contributions of Friction modifiers

So looking into is more of the quality gear oils it looks like Red Line is the only one that has a 74wt140 with no modifiers. You have to buy the 75wt140NS NS for non slip) version

I used Red Line in my 80 years ago and I can't remember why

From BITOG on ARB recommendations in Oz" That recommendation doesn't say syns cannot be used in the ARB AIr Locker, just that these oils are recommended. Pay heed to the recommendation to NOT USE limited slip friction modifier or oils that are marked on the bottle "For Limited Slips." Friction modifier reduces the oxidative stability of the oil a bit so you don't want it if you don't have to have it. "

Whether the friction modifiers actually hurt the o-rings is probably a subject of debate. I believe we can agree that the ARB does not require Friction Modifiers.

Over in the 80's section about 13 years ago the moderator created a FAQ thread on oil and gear oil. This was a compilation of other threads with help from two people who seemed to know their stuff on oil Note this is in the 80's section so you may not want to post in it. Note in post 2 cary (one of the smart guys) recommended Red Line for diffs. Most of the thread is on Motor oil

 

[LINUS]

@Romer - sounds like a good call.

It must be those friction modifiers that were what knocked out my main o-rings on the ARB’s (guessing still same design) - and @cary was a real source of info (IDK if he’s still posting) - but he’s no slouch.

Let us know how Redline works, esp if this is a new ARB locker or one you’re re-ringing like the one I had so many issues with.

I’d already forgotten if this was a new locker or if it had been ‘broken in’ & everything was setting nicely.

Strangely —- and here’s the kicker —- my RR ARB in that exact LX450 only ever needed 1 re-ringing. I’m sure it was Murphy’s law as pulling the RR 3rd was 1/4 the work of doing a full FAS just to pull & service the FR FZJ80 3rd.
And — like any RR locker, it got 3x the use any FR did. Go figure.

Either way, let us know what happens - if you get a good few yrs & uneventful / decent use without the telltale mist, Redline may be a great option too the way Amsoil basic (if there are any different flavors) - has worked for us up here in WA state general climate & humidity (I have a no-science suspicion that humidity has an effect on the additives, but that’s 100% speculation).
I only took 100’s level chemistry in college & additive packages are “kept secrets” - that don’t have a breakdown on the chem-totes, just hazard & cleanup MSDS forms.

Keep us informed, or what final product you do use - it would be a great datapoint Ken!

Thx! - Ben

 

[Romer]

Found this on Bob is the Oil Guy

LS additives for differentials are friction "modifiers" to prevent or reduce chatter in LS diffs by tuning the dynamic friction coefficient.

They don't improve gas mileage, that is the job of an additive called a Friction Reducer.

Friction Modifiers and Friction Reducers are in a class of additives called, "Friction Enhancers."

Friction Modifiers for Differentials improve Limited Slip operation, and Friction Modifiers for Manual Transmissions help the synchro assembly, are two, entirely different chemical compounds, and one cannot substitute one for the other.

I believe that would make Mobil1 Delvac then a good candidate as well

Unfortunately, it seems harder to get in the 80-140wt. I can find it in a 38lb bucket, guessing 5 gallons or slightly under

 

[Romer]

Reading through the specs I went with the 5 gallon bucket of Delvac 80-140. The other gear oils would probably be ok. Reading the description sounds like the Delvac is superior for towing and offroad use