Diff oil weight recommendation? 2018
Joined: Aug 2016
Posts: 2,767
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From: In BOOST
No, they are not wrong. The additives that used to eat yellow metals were dropped by any reputable oil manufacturer back in the 60's. The issue with using GL5 in a GL4 application is not one of corrosion it is due to how, for lack of a better word "slippy" they are. So you can use a GL5 in a gearbox that is recommended GL4, it wont eat anything but they can be to slippy to engage the synchros especially at high revs causing a bad shift. Bad shift can mean grinding of the gears = wear metal present in the oil when it is changed out. This is often confused for GL5 eating yellow metal.
API GL6 is obsolete, and has been for sometime.
Cheers,
Guy
API GL6 is obsolete, and has been for sometime.
Cheers,
Guy
Yeah this makes sense since I doubt that Motul would have a rep respond to a customer with misinformation about a sensitive/controversial topic like this.
Registered User
Joined: Jan 2004
Posts: 613
Likes: 4
From: Truro
It wasn't a rep that responded to Mr.Matchbox it was the "Direction Produit Automobile". Gotta love French job titles. He is one of the main technical guys in the Motul "Corporate Technical" team. I've met him and he really does know his stuff as you would expect. I've spent time with many technical and r&d teams from various brands/manufacturers and as you can imagine they all know their stuff, but what I find fascinating is how they all apply this knowledge slightly differently, maybe due to the individual or company philosophy to achieve their goals.
Cheers,
Guy
Cheers,
Guy
Joined: Jan 2006
Posts: 4,953
Likes: 25
From: 17 ft below sea level.
So you're saying the EC: 939-591-3 additive, used in this Motul oil as EP additive, will not chemically attack yellow metals?
https://www.machinerylubrication.com...itives-effects
And the ASTM 130D test of the Motul 75W-140 oil (don't remember if they did this test) would come back 1a or better?
https://www.machinerylubrication.com...itives-effects
And the ASTM 130D test of the Motul 75W-140 oil (don't remember if they did this test) would come back 1a or better?
Joined: Jul 2014
Posts: 13,834
Likes: 1,552
From: Chesterfield VA
Joined: Aug 2016
Posts: 2,767
Likes: 234
From: In BOOST
It wasn't a rep that responded to Mr.Matchbox it was the "Direction Produit Automobile". Gotta love French job titles. He is one of the main technical guys in the Motul "Corporate Technical" team. I've met him and he really does know his stuff as you would expect. I've spent time with many technical and r&d teams from various brands/manufacturers and as you can imagine they all know their stuff, but what I find fascinating is how they all apply this knowledge slightly differently, maybe due to the individual or company philosophy to achieve their goals.
Cheers,
Guy
Cheers,
Guy
Joined: Aug 2016
Posts: 2,767
Likes: 234
From: In BOOST
So you're saying the EC: 939-591-3 additive, used in this Motul oil as EP additive, will not chemically attack yellow metals?
https://www.machinerylubrication.com...itives-effects
And the ASTM 130D test of the Motul 75W-140 oil (don't remember if they did this test) would come back 1a or better?
https://www.machinerylubrication.com...itives-effects
And the ASTM 130D test of the Motul 75W-140 oil (don't remember if they did this test) would come back 1a or better?
Joined: Aug 2016
Posts: 2,767
Likes: 234
From: In BOOST
Registered User
Joined: Jan 2004
Posts: 613
Likes: 4
From: Truro
So you're saying the EC: 939-591-3 additive, used in this Motul oil as EP additive, will not chemically attack yellow metals?
https://www.machinerylubrication.com...itives-effects
And the ASTM 130D test of the Motul 75W-140 oil (don't remember if they did this test) would come back 1a or better?
https://www.machinerylubrication.com...itives-effects
And the ASTM 130D test of the Motul 75W-140 oil (don't remember if they did this test) would come back 1a or better?
Cheers,
Guy
Registered User
Joined: Jan 2004
Posts: 613
Likes: 4
From: Truro
To be honest it does not matter either way, EC: 939-591-3 is a chemical abstract number, it more describes the technology used rather than one specific additive to eat yellow metal. A GL5 will probably not come back as 1A in test but will more likely be a 1B on copper corrosion, and this in real world terms makes not a bit of difference to eating yellow metals in a synchro gearbox. or anything for that matter. The additive technology for GL4 and GL5 are the same, to make a GL5 you just add more ep additive. So if a GL5 oil is going to eat yellow metals, GL4 will as well because they are the same additives/technology. But they wont, and will not as I have been saying.
So by default GL5 passes all the tests for GL4, and then some.
Cheers,
Guy
So by default GL5 passes all the tests for GL4, and then some.
Cheers,
Guy