Manual Transmission Oil Analysis @ 75,000 miles

[Mark]

That's the first I've heard of this... What does the GL5 do to transmission stuff,???,, Where is the info from The Transmission manufacturers ??? I ask as I work on some Highway Transport trucks & haven't been told of this, but if true I should know as a transmission for a Class 8 truck is worth more then our cars....??? Just Thoughts.... Post the Link Info for us Please... Hey, maybe we just started another ""The Best Oil"" Thread... Let it begin

I thought this was common knowledge, & I've read several warnings related to this topic (GL-4 vs. GL-5).

I would start, however, with most oil manufacturers recommended using the type of manual transmission oil recommended for a particular vehicle -

My 2017 Mitsubishi Mirage owner's manual recommends -

Mitsubishi Motors
Genuine NEW
MULTI GEAR OIL
ECO API Classification GL-4
Viscosity range SAE 75W-80

Since GL-4 Gear Oil 75W-80 exists, I would have thought the discussion ends there. Redline MTL is an example used by most on the forum.

To address your lack of concern - This is the most common thing I have read on the topic-

"The main difference between GL-4 and GL-5 gear oils is the amount of EP additives. Sulphur/Phosphorus containing products are used as EP-additive. This additive has the purpose to prevent the occurrence of micro-welds on the gear flanks at the local high temperatures which prevail in EP circumstances (temperatures well in excess of 800℃!) GL-5 has roughly twice the amount of EP additives compared to GL-4, which is why it is often used in high-pressure circumstances such as in a front axle and rear axle differential.

Sulphur/Phosphorus additives however have an unfavourable property: they can react aggressively towards bronze and copper. This can be disastrous for the synchromesh rings of a gearbox. Therefore it is not recommended to use GL-5 in a gearbox unless the manufacturer allows this."

taken from

https://www.rymax-lubricants.com/upd...gl-4-and-gl-5/

[jbarr]

I thoroughly understand this. The formulation on European GL4/GL5 rated oils is such, that the performance is as of GL5, but does not damage messing or other alloys that GL5 would erode. A GL4/GL5 rated oil can be used for both sorts.
If you would put a straight GL5 oil in the gearbox, the parts inside would soon become covered with a black slime, actually decomposing messing alloy usually from the synchro-rings.

You understand the issues and seem to have vetted the fluid. Great deal on the oil.

[foama]

That's the first I've heard of this... What does the GL5 do to transmission stuff,???,, Where is the info from The Transmission manufacturers ??? I ask as I work on some Highway Transport trucks & haven't been told of this, but if true I should know as a transmission for a Class 8 truck is worth more then our cars....??? Just Thoughts.... Post the Link Info for us Please... Hey, maybe we just started another ""The Best Oil"" Thread... Let it begin

I certainly do not want to start another oil thread repeating long established facts and infos!



I have this info from a person working in a major, well-known oil company. There they make all sorts of different engine, gearbox, hydraulic, you-name-it oils from all sorts of different ingredients. They are one of the few companies that make individually styled/engineered oils for their clients of famous automobile competition organizations.

A GL4/GL5 (both!) rated oil can be used just as a GL4 and as a GL5 as well. No damage is done to messing, brass, copper, EPDM, or other materials. In other words, it is backwards compatible. You can expect it to be fully synthetic to meet EP goals, not HC-cracked, not mineral based. GL4/GL5 can also be used for most of the GL3 (obsolete) applications, but ask the factory or representative to make sure.

On the other hand, a GL5 (and only GL5) rated oil is certainly not suitable as a GL3 or GL4 replacement and will most probably cause damage on the long run. Mark explained that a few posts ago. Another important feature of GL5 is heavily reduced foaming.

If you are uncertain if a particular oil suits you application, get in touch with the maker and ask! They have people for answering questions, and generally answer swiftly and acurately. At least, that is how business works in this part of the world, and probably in most other parts too.

[AtomicPunk]

Fummins: isn't the "Lube Factory" a strip joint in Vancouver?

[foama]

Fummins: isn't the "Lube Factory" a strip joint in Vancouver?

Hahaharrh!
In these parts, we don't need that sort of thing, because we're not the least prude like centuries ago. Instead we very directly just say what we would like to whoever we like. Usually that leads to desired results right away or at least almost right away, and nobody has any hard feelings at all. If we want to see what underneath looks like, we simply ask, no matter if we know the person or not. Thats normal here. The year is 2022 not 1850. Btw, nice place, Vancouver.