Which of these 3 oils would you chose for the differential?

[Clan]

Originally Posted by 360beast

I used Castrol transmax 80W90 EPX in the diff of my 940.

If you have a G80 don't use LSD oil as it isn't a Limited Slip Diff it is an automatic locking differential, I'm pretty sure the G80 uses the same conventional 80W90 GL5 oil, I could be wrong on the oil grade for a G80 but definitely don't use LSD oil.

yes ! It MUST have EP in its description ( Extreme Pressure ) for a Hypoid gear Final drive Rather than non EP for a front wheel drive type Final drive.
Transmax is the most suitable for a 900 unless you have the rare Limited Slip axle of course )

[SalvadorP]

I ended up going for the Moly 75w90. Turns out the moly 80w90 is mineral and the valvoline is a blend. So I went for the 75w90 which is fully synthetic and the price today on autodoc was 16,10€/L instead of 18,25€.
Some other oils at the same price also claimed to be synthetic, but once you dig in, they never say they are fully synthetic, so you never know if it's just a blend like valvoline. Moly 75w90 was the only that had all the right characteristics and no ambiguous terms. Besides, it's not much more expensive than the mineral oils, so I think it was the best choice.

18,25€/L

[Clan]

Originally Posted by SalvadorP

I ended up going for the Moly 75w90. Turns out the moly 80w90 is mineral and the valvoline is a blend. So I went for the 75w90 which is fully synthetic and the price today on autodoc was 16,10€/L instead of 18,25€.
Some other oils at the same price also claimed to be synthetic, but once you dig in, they never say they are fully synthetic, so you never know if it's just a blend like valvoline. Moly 75w90 was the only that had all the right characteristics and no ambiguous terms. Besides, it's not much more expensive than the mineral oils, so I think it was the best choice.

18,25€/L

Is that EP rated for spiral bevel rear axles? print not clear to red on the bottle.

[griston64]

I used this in my 940 diff

https://www.millersoils.fr/en/shop/m...l-gl4-and-gl5/

[SalvadorP]

Originally Posted by Clan

Is that EP rated for spiral bevel rear axles? print not clear to red on the bottle.

Does that mean if it is hypoid and rated for extreme pressure?
Here's from there website:

Fully Synthetic Gear Oil SAE 75W-90
SKU: 1413
Fully Synthetic Gear Oil SAE 75W-90
Fully synthetic high-performance gear oil for extended oil-change intervals and extreme loads.
Approvals: API GL5, MIL-L 2105 C/2105 D

Description
Our fully synthetic gear oil is a high-performance,
high-pressure gear oil for high-load manual, auxiliary,
transaxle and hypoid transmissions which require a
lubricant according to API GL 5. High-quality, fully
synthetic base oils and modern additive technology
guarantee a wide application range for this oil as well
as optimum transmission lubrication under extreme
conditions.

distinctive high-pressure characteristics
excellent wear protection
outstanding viscosity stability
outstanding corrosion protection
reduces gearshift resistance
reduces transmission noise

[Clan]

Originally Posted by SalvadorP

Here's from there website:

Fully Synthetic Gear Oil SAE 75W-90
SKU: 1413
Fully Synthetic Gear Oil SAE 75W-90
Fully synthetic high-performance gear oil for extended oil-change intervals and extreme loads.
Approvals: API GL5, MIL-L 2105 C/2105 D

distinctive high-pressure characteristics
excellent wear protection
outstanding viscosity stability
outstanding corrosion protection
reduces gearshift resistance
reduces transmission noise

well it does Mention Extreme Pressure that should be "EP" in the specification really. SAE EP 75W-90

[SalvadorP]

Originally Posted by Clan

well it does Mention Extreme Pressure that should be "EP" in the specification really. SAE EP 75W-90

You mean it doesn't, right?

Correct me if I'm wrong, but aren't all GL5 rated for extreme pressure? Isn't that the difference between gl4 and gl5, or one of?

[SalvadorP]

Originally Posted by griston64

I used this in my 940 diff

https://www.millersoils.fr/en/shop/m...l-gl4-and-gl5/

Thank you, but I would not buy french oil.




jk

[bob12]

If you need clarification I have found Liqui-Moly helpul and responsive to an email. info@liqui-moly.de or now they have a base in th UK, info.uk@liqui-moly.com or phone 0121 7965365. There's also a question form to fill in on their website.

Bob.

[SalvadorP]

Originally Posted by bob12

If you need clarification I have found Liqui-Moly helpul and responsive to an email. info@liqui-moly.de or now they have a base in th UK, info.uk@liqui-moly.com or phone 0121 7965365. There's also a question form to fill in on their website.

Bob.

Thanks Bob, I don't really think it is necessary any further clarification in this case.
I understand what Clan means but, for all I've read, it seems that the term EP when used in the name of the product is mostly a branding/marketing thing. What really matters is the classifications (GL1, 2, 3, 4, 5, 6) and manufacturer approval type (ie Mil-L 2105 a, B, C, D, etc.)

GL-5 is the classification of oils intended for these high pressure environments. I read that GL5 oils contain roughly double the EP additives of GL4. So I am left to assume that a GL5 grade oil, saying EP in the name is just a marketing thing. Maybe some have an extra amount of these additives, but they are all required to have a minimum amount to be classified GL-5. At least, this is my understanding of it.

LS (limited slip) additives for example is a different thing, because there isn't a classification (ie GL-5) just for them. So it needs to say that it contains LS additives. But regarding EP, I don't think it is the same, because GL-5 already implies having those additives.