Good white paper on gear oil specs GL-4, GL-5.

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THIS IS THE CRITICAL ASPECT OF THE DIFFERENCES:

"When someone tells you that their GL-5 covers GL-4, remember they are correct as far as EP
protection, but that is only half the answer.

When they say their Sulfur/Phosphorous additive will not
corrode the yellow metals, they are also correct, but if there are enough to meet GL-5 protection, they
will slowly peel away your brass synchronizers."
 
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Interesting. However ...

This is a pet-peev of mine ...

Who is this guy, what are his credentials, and why (after 10 pages) does he not have some appendix of sources, credits, references, etc? I'm not saying his work is unsound; I'm just left wondering who he is and why I should believe him.
 
Dave: Surprised you haven't been on Widman's site (www.widman.biz) or read his contributions here over many years. He is an ex-pat American that runs an oil distribution/service company in the "outback" of Bolivia. Not sure what his education or training is but all of his material I've read passed my admittedly non-lube-professional smell test.

I believe this was written for a Corvair enthusiast's site. It's no more or less "legit" than anything you, I or any other non-lubrication-professional has contributed to BITOG. And for all I know, since he is working in the lubrication industry, it's possible he has credentials beyond long field experience. As to the article, the context was likely found in it's original environment... namely a Corvair forum where his expertise was perhaps better known.
 
Widman is a cool dude but has somewhat obsolete data in this paper as do some of my white papers (which needs updating).

We need to context this paper. I believe Mr. Widman (and he can correct me if necessary) wrote this about the time that some manfactureres were recomending that synchronized Manual transmissions (especially Honda) should be lubricated with motor oils such as 5W30's etc. About the same time MTL's specifically formulated for manual transmissions were appearing on the market. So there was confusion about what MTL fluids should be used.

To clarify a couple of points, the GL-4 wear protection rating for MTL's came mainly from a combination of ZDDP and sulferized, buffered olefins, and not from a Sulfur-Phosphorus (S-P) "Exteme Pressure" additive package used for differential lubricants.

As explained elsewhere in other White Papers on Manual Transmission Lubricants, the Performance Improvement (PI) package (additive package) for synchronized manual transmissions also contain a host of other chemistries for shift improvement (specialty friction modifiers), rust prevention, metal inhibitors, emulsifiers for moisture intrusion, etc.

In many MTL formulations of late, you will see lower phosphorus levels (anti-wear), and very low levels of zinc. The low level of zinc will come from a low treatment level of ZDDP for anti-oxidant purposes only. The phos will be one of the anti-wear components. The other anti-wear components will not be detected in a conventional VOA.

Early on, the only available application specific MTLs were 75W90 or 14.5 cSt lubricants. Later, due to cold weather shiftability problems, Texaco, GM, and Pennzoil brought to the market the 5W30 or 10.X cSt viscosities.

Since the time of his writing, there has been a host of new transmission designs and formulations brought to the market.


For a list of current application specific, GL-4 MTL's of various viscosities, see the last post here:

Paper on Manual Transmission Lubricants
 
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Thank you, guys. That gives me some idea of his position. It's a good read; just wondered what his perspective was as I read.

Also, it did seem to me to be a bit out of date, so to speak. What is written is only as relative as the period cycle it exists in. I often have to update my data logs to reflect the shifts in lubes.
 
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The point I was making is that even the engineers at the major lubricant companies agree with his premise that it isn't the corrosion factor that is the issue using a GL-5 rated product in a application that calls only for GL-4, it is the ability of the chemicals to literally delaminate the brass or bronze plating off the syncros.

The proof of the concern can be found in a customer query to a Mobil Lubricants specialist that replied to a concern about using a GL-5 lube in a GL-4 application as well. And the fact that MOST all the major oil and lube companies around the world offer GL-4 rated gear oils in various viscosity combinations. The question I have is WHY in the US is this not the case. It seems more than odd.

From Mobil.com site:


Question:
Clarify Comments on Use of GL-5 vs. GL-4 Gear Oil
Concerning the GL-5 gear oil, on your website you state the following: "Mobil 1 Synthetic Gear Lubricant LS 75W-90 can also be used in rear axles where API Service GL-4 lubricant is recommended." However, you also say in this "Ask Mobil" section that: "Mobil 1 Synthetic Gear Oil is recommended for all applications where a GL-5 lubricant is specified. GL-5 type lubricants, which have a higher level of additive chemistry, can be corrosive to yellow metals such as copper, brass, etc., and in these applications a GL-4 product is usually specified." Can you clarify this disconnect here? Thank you.
-- John Goetz, Newport News, VA


Answer:
There are transmission applications that recommend API GL-4 type products where we would not recommend using an API GL-5 fluid because transmissions typically have components made from “yellow” metals. However real axles where GL-4 fluids are recommended do not have “yellow” metal components. As a result, the application of an API GL-5 fluid is acceptable.
 
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it is the ability of the chemicals to literally delaminate the brass or bronze plating off the syncros.


The synchro mating components in synchronized manual transmissions are either solid brass alloys or solid composite structures. They cannot delaminate.

What we had there in the Q&A exchange was a confused questioner who was uneducated in gear lubes, and a responder from Mobil who didn't know what he was talking about.

Again, GL-4 and GL-5 are protection ratings. A GL-4 gear oil can be a lube which offers protection for lightly loaded gear trains, whereas a GL-5 gear lube is for highly loaded hypoid differentials or HD truck transmissions.

A Manual Transmission lube is usually rated GL-4 because the gear train is not as highly loaded as a hypoid differential.
 
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I believe the only current API gear oil ratings are MT-1 and GL-5. Everything else is obsolete and has no oversight. But I'm not sure if gear oils ever had much oversight by API. It would be nice if PQIA could get involved with gear oil some day.
 
From

API Gear Oils and GL-4


Quote:
A second method is to document performance by running selected tests that are similar to the original API GL-4 tests listed in ASTM STP 512A. However, technical judgment is required to make a proper choice of test method and test results, and varies greatly within the industry, said Buzdygon.


And from

Lubrizol - Gear Oil Classifications

Quote:
API Category GL-4 designates the type of service characteristic of spiral-bevel and hypoid gears in automotive axles operated under moderate speeds and loads. These oils may be used in selected manual transmission and transaxle applications.


While the GL-4 rating may be obsolete, the industry has to have a gear protection rating for gear loadings that are lower than in high offset differentials, and one applicable for manual transmissions.

Until a better and more well defined rating comes along, the GL-4 rating is the rating in which we have to work.
 
Originally Posted By: MolaKule


Until a better and more well defined rating comes along, the GL-4 rating is the rating in which we have to work.


And with the glaring EXCEPTION of the US and Canada, the lubricant industry and the leading oil companies like Mobil, Shell, Valvoline, Citgo, BP (Castrol) and most others have agreed because in the rest of the world, they continue to sell many lines of GL-4 rated lubricants which include 75w-90, 80w-90, and other viscosity.
 
Originally Posted By: antiqueshell
Originally Posted By: MolaKule


Until a better and more well defined rating comes along, the GL-4 rating is the rating in which we have to work.


And with the glaring EXCEPTION of the US and Canada, the lubricant industry and the leading oil companies like Mobil, Shell, Valvoline, Citgo, BP (Castrol) and most others have agreed because in the rest of the world, they continue to sell many lines of GL-4 rated lubricants which include 75w-90, 80w-90, and other viscosity.


Forgive me, but I do not see your point.

Many companies have dual-rated lubricants, but most are for industrial gearbox and mainly differential applications.

For the majority of light truck and passenger car vehicles with Manual Transmissions, a GL-4 rating is all that is needed.

There are exceptions such as Subaru which apparently specs GL-5 MTL's, but they are the exception, so why should I make a GL-5 MTL when the market would not currently support an exception.

I suspect that in the future if and when Suburu's become more numerous and stay in the market, more companies will supply GL-5 and dual rated MTL's.
 
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You misunderstood my point.

That it is VERY difficult, almost IMPOSSIBLE today in the US to find a major oil company brand of GL-4 ONLY gear oil.

Try and find a bottle of 75w-90 or even 80w-90 GL-4 spec oil that is made by other than Amsoil or Redline. The consumer cannot readily find it. Amsoil and Redline products are expensive and overkill for most ordinary passenger cars with manual transmissions.
 
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Quote:
That it is VERY difficult, almost IMPOSSIBLE today in the US to find a major oil company brand of GL-4 ONLY gear oil.

Try and find a bottle of 75w-90 or even 80w-90 GL-4 spec oil that is made by other than Amsoil or Redline. The consumer cannot readily find it. Amsoil and Redline products are expensive and overkill for most ordinary passenger cars with manual transmissions.




Are you speaking to Manual Transmission oils exclusively?

Pennzoil makes a Manual Transmission Oil called Pennzoil Synchromesh.

I suspect the major oil companies don't see a large enough market for the the 14 cSt (75W90) type MTLs, which is why Amsoil and Redline fill that void with their niche product.

I disagree with your statement about them being expensive and overkill. A simple GL-4 gear oil (non-MTL) for general gearbox use does not have all of the components necessary for proper synchro performance in an MTL.
 
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Originally Posted By: MolaKule


Are you speaking to Manual Transmission oils exclusively?

Pennzoil makes a Manual Transmission Oil called Pennzoil Synchromesh.

I suspect the major oil companies don't see a large enough market for the the 14 cSt (75W90) type MTLs, which is why Amsoil and Redline fill that void with their niche product.

I disagree with your statement about them being expensive and overkill. A simple GL-4 gear oil (non-MTL) for general gearbox use does not have all of the components necessary for proper synchro performance in an MTL.


The Pennzoil Synchromesh is ONLY for some GM and Chrysler vehicles and it is NOT GL-4 spec even though Pennzoil "claims" it is safe for use with yellow metals in manual transmissions.

Many of us have European cars with manual gear boxes that specifically state that ONLY GL-4 spec 75w-90 be used.

This even applies to European cars in current production that are for sale in the USA.

Why doesn't Shell simply offer a Euro spec product that meets that spec for sale in the USA. It wouldn't cost them anything since the product is already offered in the rest of the world and they can distribute it through Pennzoil?
 
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You answer my question first:

Quote:
Are you speaking to Manual Transmission oils exclusively?


Quote:
The Pennzoil Synchromesh is ONLY for some GM and Chrysler vehicles and it is NOT GL-4 spec even though Pennzoil "claims" it is safe for use with yellow metals in manual transmissions.


Who told you it wasn't a GL-4 MTL? Yes it is a GL-4 spec oil because it contains a GL-4 protection additive package.

See my list of MTL GL-4 oils for synchronized transmissions at the end of the post:

MTL GL-4 Lubricants of Various Viscosities

Quote:
Many of us have European cars with manual gear boxes that specifically state that ONLY GL-4 spec 75w-90 be used.


Oh boy, here we go again.

For example and for discussion purposes, here is a gear oil made by Amsoil that carries a GL-4 and GL-5 rating.

Amsoil Marine Gear Lube

Now, please tell us why the above oil is better than these MTL Specific GL-4 transmission lubes below such as

Amsoil MTG

or

Redline MTG MTL

which have GL-4 additive packages.

As far as your gripe with Shell, I would ask them why them don't market the oils in the US. Personally, I don't think their costs would be any lower than Amsoil or Redline.

If you purchase a foreign car with with a weird lube spec then you may have to deal with the often expensive fluid requirements.
 
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I am speaking of manual gear boxes. There are still plenty in the world and plenty are still even sold in the USA. Not to mention that the majority of passenger vehicles in Europe still use a manual transmission box with synchronized gears.

As for Pennzoil Synchromesh I see nowhere in their data sheet that the fluid meets GL-4 specifications. Please direct me to where you see that on an official up to date SOPUS sheet.

Also we don't know what the viscosity of that gear oil is, I can't find it listed ANYWHERE on the product itself or the data sheets.
 
I guess the point I was making in post #3064721 did not somehow register.

Here was the point:

A GL-4 rating for a gear lube signifies a certain level of protection for bearings and protection for gear configurations that do not have a high loading. Loading here means the amount of torque experienced and the forces and reactions on gear teeth and thrust washers.

A generic GL-4 gear lube such as the Amsoil Marine Gear Lube and others, DO NOT CONTAIN the friction modification chemistry necessary for synchronizer assemblies.

In other words, a generic GL-4 gear lube is NOT EQUAL to an Application Specific Manual Transmission Lubricant with a GL-4 rating.
 
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I looked closely at the Syncromesh data sheet and NOWHERE on it does it state it meets API GL-4 specification.


Plus that viscosity appears to be pretty thin, must be lower than 75w, correct?

I understand what you are saying about certain general gear lubes FM not being adequate for synchronized gear boxes.


--------------------------------------------
bottom line for me....


What is the viscosity of Pennzoil Synchromesh in traditional API weight?


Does Pennzoil Synchromesh pass the

ATSM D-130 copper corrosion test with a
1a or 1b classification.

Can I use it in my 1996 Volkswagen Golf GL
with 5 sp manual transmission?
 
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