Diff oil weight recommendation? 2018
#261
I do not know if they could go as far as 0w-90, interesting question though. The problem with it would be how quickly it would shear down and drop out of grade. The larger the viscosity gap the more viscosity index improver is needed to bridge the gap and these can shear down easily in an engine let alone a diff. It is the same reason there is a common viscosity gap between certain grades, such as 0w-30/5w-30/0w-40/5w-40 then when you get to the SAE50 it kind of goes 5w-50/10w-50/15w--50/20w-50 up at the top end SAE60 you have 10w-60/15w-60/20w-60. They could make a 0w-60 I guess if they wanted but it would very soon be running as a 0w-40 or less as it shears down and stops doing a good job.
Cheers,
Guy
Cheers,
Guy
#262
Much of the question comes down to "what's good enough?" In the engine 10W-30 oil temperature intuitively rises to 100°C much faster than than a 75W-90 gear oil will. I suspect the homework for this was done by the engineers designing the systems and needs no tweaking by we mere mortals for other than specialty applications.
-- Chuck
-- Chuck
#263
I understand multi-grade and am aware that the operating temp is the highest number whereas the lowest number is for cold temp "starts." However, I read somewhere that the wider the range, the more prone to sheer it is. Perhaps the individual didn't know what he was talking about. Regardless, the old 90W is the new 110W as has been mentioned before.
#265
I understand multi-grade and am aware that the operating temp is the highest number whereas the lowest number is for cold temp "starts." However, I read somewhere that the wider the range, the more prone to sheer it is. Perhaps the individual didn't know what he was talking about. Regardless, the old 90W is the new 110W as has been mentioned before.
The old SAE90 is not the new SAE110, if that was the case what is the current SAE90? It is still the old one. The viscosity range for SAE90 was effectively cut in half and the higher viscosity half became SAE110, but this is a non issue as according to what I have seen back then most SAE90 oils were not in that higher range of the viscosity bracket anyway. This is why no car manufacturers have retrospectively changed their diff recommendations to SAE110 or recommending it going forward because it was not the norm.
Cheers,
Guy
#266
Registered User
The problem with multigrade oils is, that the viscosity improvers shear down, that causes the oil to get much thinner over time in use.
Some shear down fast, some slow. In a gearbox, the stress for the viscoity improvers is much higher than in an engine.
Thats why a monograde oil like a SAE 90 is a good idea in a differential. It will last longer.
Nobody could say wich kind of viscosity improver the oil manufacturer uses. A virgin oil analysis also dont show it.
But for sure, the better viscosity improvers are more costly for the oil manufacturer.
Her is a PDF from RAVENOL with a little bit of Information about this:
https://www.ravenol.de/fileadmin/con...esentation.pdf
Some shear down fast, some slow. In a gearbox, the stress for the viscoity improvers is much higher than in an engine.
Thats why a monograde oil like a SAE 90 is a good idea in a differential. It will last longer.
Nobody could say wich kind of viscosity improver the oil manufacturer uses. A virgin oil analysis also dont show it.
But for sure, the better viscosity improvers are more costly for the oil manufacturer.
Her is a PDF from RAVENOL with a little bit of Information about this:
https://www.ravenol.de/fileadmin/con...esentation.pdf
Last edited by Mr.Matchbox; 10-30-2018 at 02:19 AM.
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Opie Oils (10-30-2018)
#267
Registered User
Just for sharing Information:
I discoverd two differential oils from PENRITE that carry GL6 (!) approval.
https://www.penriteoil.com.au/applic...-90-full-syn#/
(This one also carry the ZF TE-ML 19C approval, to my limited knowledge the most strict and demanding specification for differential oils.)
https://www.penriteoil.com.au/applic...f-oil-80w-90#/
I discoverd two differential oils from PENRITE that carry GL6 (!) approval.
https://www.penriteoil.com.au/applic...-90-full-syn#/
(This one also carry the ZF TE-ML 19C approval, to my limited knowledge the most strict and demanding specification for differential oils.)
https://www.penriteoil.com.au/applic...f-oil-80w-90#/