Opie Oils

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

simons

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?

simons

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?

windhund116

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.

simons

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?

simons

In Holland Amsterdam area

simons

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.

windhund116

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.

dedonderosa

Lubrication Engineers LE1605 is the only way to go imo

simons

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)