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Diff oil weight recommendation? 2018

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Diff oil weight recommendation? 2018

 
Old 09-11-2018, 03:29 AM
  #21  
 
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Originally Posted by simons View Post
okay, so I have to choose between 80w90 or 85w140. No amsoil available here. Both oils are mineral hypoid. No limited slip. Just regular gear oil.

I have no idea what the difference to the diff would be. And if I would be able to feel it?

The local honda service dealer drops in 80w90. But perhaps thats just what they have available.

please advice! Thanks again
I don't know what you have available to you but here in the UK the stock viscosity is SAE90 GL5, but we also recommend 75w-90 synthetic GL5 as most 80w-90 diff oils are mineral, or they are in the UK. Why are people running 75w-140 in stock diffs?

Cheers,

Guy
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Old 09-11-2018, 04:29 AM
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Originally Posted by Opie Oils View Post
Hi,

75w-90 and 75w-140 are the same viscosity when cold, the only difference is when hot and the viscosity of the SAE140 is thicker than the SAE90. How this effects the way the diff performs in theory is the thinner the oil the more aggressive the lsd becomes as the thinner oil will allow it to lock quicker, you can also play around with friction modifiers that also affect how the lsd behaves.

Cheers,

Guy
If your explanation is correct, than why would track guys use a thicker oil? Wouldnt they bennefit from a quicker and more aggressive locking diff for having better on power traction? Or am I not understanding the point of a lsd?
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Old 09-11-2018, 04:35 AM
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Originally Posted by Opie Oils View Post
I don't know what you have available to you but here in the UK the stock viscosity is SAE90 GL5, but we also recommend 75w-90 synthetic GL5 as most 80w-90 diff oils are mineral, or they are in the UK. Why are people running 75w-140 in stock diffs?

Cheers,

Guy
thanks for your input!

Why would you spent 2 or 3 times what you pay for in mineral? At least here that is for a synthetic, and most are for LS diffs (not torsen) so we dont need that additive I was told.

Besids the all rcommended tranny oil is Honda MTF and its mineral too. So why does the diff need a synthetic? I understand it for the engine because it spins like crazy, with the highest loads in the drivetrain.At least that is what I assume because that is where the power starts... And there is a burning proces in the engine that the oil gets contimminated with. But the diff is a closed box, with no combustion proces.
Why would you recommend a synthetic? And would you say you can use it for more kms and more years than a regular mineral instead?
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Old 09-11-2018, 04:37 AM
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I believe that much of the differential fluid's job is to dissipate heat generated from the friction of the gears within the unit. As gear lube breaks down, the gears are subject to wear. 140W prolly holds its lubricating property better, under heat and pressure than 90W.
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Old 09-11-2018, 04:38 AM
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Originally Posted by flanders View Post
Why would you not use a synthetic?
To save some bucks. I dont see why a synthetic is neccesary for the diff. There is no combustion in the diff, no contamination. Its more equal to the gearbox, wich runs on honda mtf mineral, and is widely recommended.
PLease explain otherwise why I should use the synth?

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Old 09-11-2018, 04:42 AM
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Originally Posted by alSpeed2k View Post
Where are you located?
In Holland Amsterdam area

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Old 09-11-2018, 04:50 AM
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Originally Posted by windhund116 View Post
I believe that much of the differential fluid's job is to dissipate heat generated from the friction of the gears within the unit. As gear lube breaks down, the gears are subject to wear. 140W prolly holds its lubricating property better, under heat and pressure than 90W.
To start, a thicker oil will get hotter than a thinner one, due to higher friction. So if you want it to cool down quickly, thicker is not better. Im sure there are reasons to use 140, but so far I havent heard a good explanation why its better than what Honda decided to use for the car. And since nobody feels the difference in diff action, nor has anybody had problems with their diff with either 75w90 or 75w140 i'm not convinced what I should buy.

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Old 09-11-2018, 05:03 AM
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Diff oil getting hotter is prolly the idea here. Heat transfer from the gears to the case. As well as stability under hotter, heavier loads.
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Old 09-11-2018, 05:17 AM
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Lubrication Engineers LE1605 is the only way to go imo
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Old 09-11-2018, 05:52 AM
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I found a place here that sells the mentioned Amsoil 75w140 oil but it costs 45 USD incl shipping. While I can pickup 80w90 GL5 gear oil locally for 15.
And Oem Honda sae 90 GL5 for 52 bucks!
Is the 80w90 fine or should I pay the premium? Will the Amsoil last longer than the 80w90 mineral gl5? (amsoil is synthetic)
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