Diff oil weight recommendation? 2018
Joined: Jan 2006
Posts: 4,953
Likes: 25
From: 17 ft below sea level.
You can do 
all day, it won't change anything.
Just like "The Diff" doesn't know it's in a car so it will explode with the new LE1605 without that GL-5 rating.
LE-1605 is still an ISO 220 oil with an AGMA EP5 rating and that's pretty good stuff.
Plus I think the industry standard test results will be as good or better than the old LE-1605.
So stop doing and use it.
all day, it won't change anything.Just like "The Diff" doesn't know it's in a car so it will explode with the new LE1605 without that GL-5 rating.
LE-1605 is still an ISO 220 oil with an AGMA EP5 rating and that's pretty good stuff.
Plus I think the industry standard test results will be as good or better than the old LE-1605.
So stop doing
and use it.
Joined: Jul 2014
Posts: 13,832
Likes: 1,550
From: Chesterfield VA
regarding the introduction of a random tire discussion out of nowhere and a later weak attempt by someone else to justify it regarding differential lubrication (or was that justification tongue in cheek?). No problems or head banging on my end regarding the oil discussion. I won't use the new formula non-GL5 LE-1605 or another non-GL5 oil.
-- Chuck
Thread Starter
Joined: Oct 2010
Posts: 254
Likes: 8
TW 180 tires are certainly relevant in a differential oil post.
Picture this:
You're on TW180 tires, sunny day, twisty road (that you know) and you're having fun driving uphill.
As it's uphill you only use 2nd and 3rd gear TILL REDLINE
as the turns follow eachother quickly.
You're approaching a sharp hairpin turn, righthander, pretty much 180 degree.
You just passed some simpl left/right/left combo turns you took in 2nd and you just about reach redline in 2nd as you start to brake for the hairpin.
You get as close to the center line as possible (it's still a PUBLIC ROAD you know) to be able to clip the apex just right.
As you trail brake you smoothly turn in, looking THROUGH the turn and because it's uphill you feel the car sink in a little and grab the road, you have GRIP!
As you start to straighten the steering wheel you smoothly apply the throttle, as much as the imaginary link between steering and throttle allows.
WTF!
The front starts to push out a bit!
WTF!
Is this a FWD car?
Why am I having oversteer?
It all works out but you start to wonder.
Should I now spend $3k or more in coilovers, springs, lowering, etc, ect, to make this behavior go away?
You should not.
You should spend $20 on a bottle of 75W110 or 75W140 for you diff.
That'll fix it.
Because your Torsen LSD locked-up a bit too much because that diff water you have in there could not handle the stress in the Torsen and changed how the Torsen locked.
You see?
This is why TW180 tires are relevant in this thread.
Without the grip you would never have noticed this behavior.
And using that 75W110/140 you will never ever find anything bigger than a 1mm thinner-than-paper flake and some dust on your magnetic diff drain.
Even after using it for 32000km.
Picture this:
You're on TW180 tires, sunny day, twisty road (that you know) and you're having fun driving uphill.
As it's uphill you only use 2nd and 3rd gear TILL REDLINE
as the turns follow eachother quickly.You're approaching a sharp hairpin turn, righthander, pretty much 180 degree.
You just passed some simpl left/right/left combo turns you took in 2nd and you just about reach redline in 2nd as you start to brake for the hairpin.
You get as close to the center line as possible (it's still a PUBLIC ROAD you know) to be able to clip the apex just right.
As you trail brake you smoothly turn in, looking THROUGH the turn and because it's uphill you feel the car sink in a little and grab the road, you have GRIP!
As you start to straighten the steering wheel you smoothly apply the throttle, as much as the imaginary link between steering and throttle allows.
WTF!
The front starts to push out a bit!
WTF!
Is this a FWD car?
Why am I having oversteer?
It all works out but you start to wonder.
Should I now spend $3k or more in coilovers, springs, lowering, etc, ect, to make this behavior go away?
You should not.
You should spend $20 on a bottle of 75W110 or 75W140 for you diff.
That'll fix it.
Because your Torsen LSD locked-up a bit too much because that diff water you have in there could not handle the stress in the Torsen and changed how the Torsen locked.
You see?
This is why TW180 tires are relevant in this thread.
Without the grip you would never have noticed this behavior.
And using that 75W110/140 you will never ever find anything bigger than a 1mm thinner-than-paper flake and some dust on your magnetic diff drain.
Even after using it for 32000km.
"Why am I having oversteer?"
Because you dont
When the front pushes out as you described, its called UNDERsteer, not oversteer.
Secondly, if you run "diffwater" as you call a thinner oil, you say this causes power understeer. But what proof do you have to back this up?
Joined: Aug 2012
Posts: 8,759
Likes: 1,861
I think oversteer was just a typo. He clearly meant understeer, as he described the effect the driver felt, front end pushing.
It should also be clear that was an attempt at humor, to find some lengthy, drawn out clever reason why a tire discussion legitimately belongs in a diff oil thread, when clearly it does not. Yet he managed to find a way to make it relevant. So kudos to him.
It should also be clear that was an attempt at humor, to find some lengthy, drawn out clever reason why a tire discussion legitimately belongs in a diff oil thread, when clearly it does not. Yet he managed to find a way to make it relevant. So kudos to him.
Joined: Jan 2006
Posts: 4,953
Likes: 25
From: 17 ft below sea level.
But it will after a while.
Because the high offset final drive is chewing up your diff oil, that's the nature of that final drive (remember the original GL-6 recommendation?)
I went to a Honda dealership at some point and aksed them to check the electric power steering because I experienced this behavior.
I was still new to the car, within 2 years of ownership.
Note I had recently been in for a service at another dealership I went to for years and I bought cars - but not the S2000 - from.
They also changed diff oil.
All - and I really mean ALL - the Honda dealer did was change the whatever-was-in-the-diff oil for Honda Marine SAE 90 GL-5.
After the first roundabout - we, as you know, have a lot of those in the Netherlands - I was smiling again.
The nose kept pointed where I pointed it.
Over the years I based my diff oil changes on how the car - or better, the Torsen LSD - behaved.
The Honda Marine SAE 90 GL-5 did eventually also do this (shear down, chewed up by the ring & pinion) and I searched a lot to get the at that point famous LE-607 and actually found it and used it.
I still have an unopened bottle of it.
As I then installed the 4.57's and Richmond Gear recommened 75W-140 I never went thinner.
As the other LE gear oils are very hard to come by - ask Chuck - I started using Amsoil.
Do what you want with this info, I know what I felt in the car and I know it was fixed with fresh - and better - diff oil alone.
The S2000 will talk to you when you drive it and it will let you know what you do right and wrong.
Problem is, the parts that are wrong (shitty tires, bad alignment and the idiot behind the wheel too) shout out loud and block the LSD whispering "I'm locking a bit too much but that's because the R&P have destroyed the oil, please change it"
Sorry for the long story.
Joined: Aug 2016
Posts: 2,767
Likes: 234
From: In BOOST
Not straight away.
But it will after a while.
Because the high offset final drive is chewing up your diff oil, that's the nature of that final drive (remember the original GL-6 recommendation?)
I went to a Honda dealership at some point and aksed them to check the electric power steering because I experienced this behavior.
I was still new to the car, within 2 years of ownership.
Note I had recently been in for a service at another dealership I went to for years and I bought cars - but not the S2000 - from.
They also changed diff oil.
All - and I really mean ALL - the Honda dealer did was change the whatever-was-in-the-diff oil for Honda Marine SAE 90 GL-5.
After the first roundabout - we, as you know, have a lot of those in the Netherlands - I was smiling again.
The nose kept pointed where I pointed it.
Over the years I based my diff oil changes on how the car - or better, the Torsen LSD - behaved.
The Honda Marine SAE 90 GL-5 did eventually also do this (shear down, chewed up by the ring & pinion) and I searched a lot to get the at that point famous LE-607 and actually found it and used it.
I still have an unopened bottle of it.
As I then installed the 4.57's and Richmond Gear recommened 75W-140 I never went thinner.
As the other LE gear oils are very hard to come by - ask Chuck - I started using Amsoil.
Do what you want with this info, I know what I felt in the car and I know it was fixed with fresh - and better - diff oil alone.
The S2000 will talk to you when you drive it and it will let you know what you do right and wrong.
Problem is, the parts that are wrong (shitty tires, bad alignment and the idiot behind the wheel too) shout out loud and block the LSD whispering "I'm locking a bit too much but that's because the R&P have destroyed the oil, please change it"
Sorry for the long story.
But it will after a while.
Because the high offset final drive is chewing up your diff oil, that's the nature of that final drive (remember the original GL-6 recommendation?)
I went to a Honda dealership at some point and aksed them to check the electric power steering because I experienced this behavior.
I was still new to the car, within 2 years of ownership.
Note I had recently been in for a service at another dealership I went to for years and I bought cars - but not the S2000 - from.
They also changed diff oil.
All - and I really mean ALL - the Honda dealer did was change the whatever-was-in-the-diff oil for Honda Marine SAE 90 GL-5.
After the first roundabout - we, as you know, have a lot of those in the Netherlands - I was smiling again.
The nose kept pointed where I pointed it.
Over the years I based my diff oil changes on how the car - or better, the Torsen LSD - behaved.
The Honda Marine SAE 90 GL-5 did eventually also do this (shear down, chewed up by the ring & pinion) and I searched a lot to get the at that point famous LE-607 and actually found it and used it.
I still have an unopened bottle of it.
As I then installed the 4.57's and Richmond Gear recommened 75W-140 I never went thinner.
As the other LE gear oils are very hard to come by - ask Chuck - I started using Amsoil.
Do what you want with this info, I know what I felt in the car and I know it was fixed with fresh - and better - diff oil alone.
The S2000 will talk to you when you drive it and it will let you know what you do right and wrong.
Problem is, the parts that are wrong (shitty tires, bad alignment and the idiot behind the wheel too) shout out loud and block the LSD whispering "I'm locking a bit too much but that's because the R&P have destroyed the oil, please change it"
Sorry for the long story.
Is/was the Honda Marine SAE90 GL5 full synthetic?