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Articles on Gear Oil

Started by SHOdded, February 23, 2018, 02:37:52 AM

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SHOdded

http://www.widman.biz/uploads/Transaxle_oil.pdf

QuoteThe Difference between GL-4 and GL-5 gear oils
by Richard Widman
Revision 6-2017

The original target audience for this paper was my group of friends in the Corvair world, but it applies
to all cars and is particularly important for all classic cars.
There is a lot of confusion about gear oils and the API classifications. In this paper I will try to
differentiate the two oils and clear up the mysteries that are flying all over the internet. It is extremely
common, or normal, for all GL-5 oils to claim they cover the API GL-4 requirements for gear oils. This
is a true statement. Does that make them satisfactory for synchromesh or synchronized transmissions?
NO! They meet the GEAR OIL specifications, not transmission oil specifications. The API GL-4 and
GL-5 categories do not mention or have anything to do with transmission synchronizers.
History:
The gear oils of a few decades ago had lead additives that were effective at wear reduction, but not very
good for the environment. A long time ago they began to be replaced by gear oils with a phosphorous
additive (in itself a decent anti-wear additive) with active sulfur to grip hold of the gears and create a
very solid sacrificial layer of material that could be worn off, thereby protecting the gear surface.
Eventually it was discovered that the active sulfur was causing corrosion of brass and other soft metals
used in differentials and transmissions.
Somewhere around 25 years ago a deactivated or buffered sulfur was developed that would react with
the phosphorous to create the protective/sacrificial layer in the conditions created in the gear boxes
(temperature and pressure) without being corrosive to the brass, copper, etc. This additive system is
used in most gear oils today.
The problems arise when we try or need to use the same product in the transmission that we use in the
differential. Many people have called oil companies and been told by the "Techs" that answer their
questions that their oils have buffered sulfur and therefore are not corrosive to yellow metals, so their
GL-5 oils can be used with brass components. While that answer is totally correct, it does not address
the question asked: Can I use your GL-5 in my synchromesh transmission?
Let's take a look at the API GL-5 rating. It is a rating for EP (Extreme Pressure) protection. The higher
the EP protection, the higher the GL category. In the mid 60's, Ford needed better protection in their
pickup trucks and GM developed the front wheel drive Oldsmobile Toronado that had a differential
with a very high angle of contact for power transmission to the wheels so a higher category was
developed (later to be called GL-6) to offer the protection needed. This level of protection can still be
claimed, but can no longer be tested since the Toronado rig used to test it is no longer available. (Note:
The 1966 and 1967 Toronados had sun gears between the axle shafts instead of spyder gears and a very
high offset, while suffering from the high temperatures of the engine compartment and very high
pressures.) This is why you will frequently see GL-6 listed as "obsolete". The test is obsolete, not the
car or its needs. Many other high performance cars continue to spec this level of EP performance.
In normal operation, the sulfur/phosphorous additive forms a black sacrificial coating on the gears and
anything it touches with a little pressure and temperature. As the gears turn, instead of wearing, the
sacrificial coating of additives is peeled off or worn off. This is normal and acceptable in all steel gears.
But when one or more of the surfaces is brass or another soft metal, the sacrificial coating is stronger
than the base metal, and instead of just peeling off, it takes with it a few microns of brass that it is
bound to.
The Difference between GL-4 and GL-5 gear oils 2 of 12
A traditional GL-4 gear oil of any given viscosity has about ½ of the level of sulfur/phosphorous
additive that would be in the GL-5 product, so the bond is not as strong, and therefore can be peeled off
without peeling a layer of brass (or less brass). This means that the GL-4 product provides a little less
extreme pressure protection, so in the differential of a high-powered car, it would not be the ideal
product in the differential. To understand this need we should be aware of the fact that the differential is
where the final torque is applied to the wheels (in most applications).
But in the transmission, we should consider two factors:
• Due to the fact that the differential applies the final torque, normally we do not need the full EP
protection in the transmission where less torque (about 30%) is applied.
• We need to be able to break the EP protection to stop the spinning of the gears long enough to
mesh them or synchronize them.
When we use a GL-5 product in a transmission that requires GL-4, we normally find 2 to 4 times as
much copper in the used oil as we would with a GL-4 product (with used oil analysis). Eventually the
synchronizers wear to the point that they no longer make contact with the other half of the cone,
bottoming out before stopping the opposing gear. (Refer to the picture below.)
GL-3
It should be noted that while GL-3 is frequently considered obsolete since it has less protection than the
GL-4, some transmission manufacturers today specify GL-3 (Chrysler and Mitsubishi among them).
There are many formulations of GL-3 oils in the market, some with sulfur/phosphorous additive and
some with zinc/phosphorous. Almost any diesel motor oil classifies as a GL-3 or GL-4 in gear
protection.
Synchromesh transmission oils
General Motors, Honda and others have developed oils that combine the best shift characteristics with
their transmission components for reduced wear. These products in general could classify as GL-4 oils
if they wanted to, but actually when we analyze their components they are very similar to 5W-30 diesel
motor oils, with a few friction modifiers added. The viscosity is closer to an ATF. They are way too thin
for a Corvair transmission or any other where a SAE 80W-90 or 75W-90 is recommended.
Modern transmission oils
I am getting questions about the application of traditional GL-4 or GL-5 oils in modern cars
or the use of modern transmission oils in classic cars, so let's look into them.
A lot of study has gone into the development of oils that are more slippery, more protective, and more
efficient. The current emphasis on fuel economy has driven many new transmission designs and oils to
match them. The economy gains have come with gear and machining design (smaller synchronizers
with double sided contact surfaces fused onto the ring) in an assembly that not only permits, but
requires, thinner oils. They also cannot tolerate sulfur/phosphorous additives in the oil, depending on
friction modifiers and new compounds to achieve GL-4 or better performance. This can become
confusing, as few lubricant manufacturers state their ingredients. All you see are claims for
performance or recommendations for their own brand. In most cases these new formulations are much
better for the transmission and its efficiency.
For the most part these are SAE 75W-80 and 75W-85 oils. Way too thin for most classic cars, but
necessary for modern cars. The additive package uses magnesium or calcium sulfonate compounds and
often synthetic base oil, and will give you better EP protection than a GL-4 sulfur/phosphorous oil.
The Difference between GL-4 and GL-5 gear oils 3 of 12
Many of these claim GL-4+ performance and pass most of the old GL-5 and SAE J2360 extreme
pressure tests, but additionally pass manufacturers tests for synchronization. The problems of where to
apply them lie with the auto manufacturers, where, for example, Toyota specifies in their owner's
manual, their SAE 75W without defining the rest of it. Oil sales people will sell you 75W-90, but what
Toyota is really asking for is 75W-85 without sulfur/phosphorous. From the comments I receive, a
standard SAE 75W-90 GL-4 does cause hard shifting and grinding in these Toyotas in 70ºF weather.
Nissan has the same problem with 75W-90 oil, but their manual clearly states 75W-80 for 6 speed
transmissions and 75W-85 for 5 speed transmissions. It does not specify "non sulfur/phosphorous" oil,
instead referring to "Genuine Nissan Oil" (which does not contain those additives).
VW calls for 75W oil that meets their spec. They are looking for a viscosity on the low end (or slightly
below) of a 75W-80 and no sulfur/phosphorous additives.
With these new non-sulfur/phosphorous oils giving a minimum of GL-4 extreme pressure protection, I
believe manufacturers will stop specifying GL-3 when they revise their manuals. Recommendations are
also coming out from the additive makers to use these new formulations in place of the older
Synchromesh Fluids.
Transaxles
So, what do we put in transaxles where the transmission and differential are combined in one unit? This
is a good question, and the answer lies in the design and surface area of the gears. If the contact
surfaces of the gears are big enough to carry the weight and torque necessary, we depend less on the oil
and its additives. If the surface area is compact, we need to depend more on the additive's ability to
handle the boundary lubrication. When we have transaxles, we have to depend on the manufacturer to
tell us what product is correct.
When we have transaxles, we also need to be aware of whether the differential portion uses Limited
Slip "LSD" technology of some kind that limits the slipping of the wheels in mud and snow. This
requires an additive that lets a clutch bind the wheel movement together at a certain speed differential
of the wheels. This additive can be in any oil. Many GL-5 oils have a small amount. This is often
enough for some differentials as long as they were not rinsed out. Some systems need more additive
than others. You can usually tell if you need more additive by making a U-Turn. If the inner wheels
click or try to lock up on the turn, you need more additive. Often an oil that has a little of this additive
will say it is satisfactory for "service fill" or "top-off".
How can you tell whether or not you have a limited slip differential? That is the easy part: Jack up both
driven wheels and spin one of them with your hand (transmission in neutral) if the other wheel spins
the same way, you have a limited slip differential. If it spins in the reverse direction, you do not. You
can also just jack up one wheel and try to spin it. If it refuses to turn, or turns with a lot of resistance,
and the car is in neutral, with no brake on, you have limited slip
You will find numerous wrong comments on forums and other sites where users claim that GL-4
means LSD. That is totally false. A check of the API site could have set them straight.
Engine/Transaxle combinations
While not used in any Corvairs, there are cars where the same oil sump is used for lubrication of the
engine, transmission, and differential. With this design, the parts of the transmission and differential are
dimensioned for use of a GL-4 (or perhaps at one time even a GL-3). My 1975 Morris Mini is an
The Difference between GL-4 and GL-5 gear oils 4 of 12
example of these cars. As far as I know, most have been fairly low HP engines, and where the higher
HP (turbo versions) were offered, synthetic oil was recommended. One caution that is not often
mentioned in those manuals: The multigrade oils used should be group II or stronger, or you should
avoid extending the interval beyond what is mentioned. The lesser quality multigrade oils tend to get
their polymers ground or sheered in the gears, just like some of the sludge prone OHV engines of today
where gears are used for synchronization of the cam and crank. Note: Corvair engines do not suffer
from this sheer due to the large diameter of the cam/crankshaft synchronization gears in the engine.
We can also note that the Chevrolet Luv pickups, as well as the Isuzu Rodeo and Trooper and many
others have recommended motor oil in the transmission for many years, even though they have
separate compartments. They only use gear oil in the differential.
The concept of using motor oil in these situations goes back to what I said towards the beginning. Most
motor oils can qualify for GL-4 (or at least GL-3) EP protection. As long as the torque on the gears in
low speed sliding action does not exceed what is covered by the GL-4, there is no benefit to
sulfur/phosphorous additives, but there is one for the synchronizers.
In the case of those single compartment motor/transaxle, there is an additional benefit of constantly
filtering the oil. The risk is that if you get gasoline in your oil you will thin out hydrodynamic film
protection in the gears. If you are running a mixture too rich, the additional soot (carbon particles) will
wear the gear surfaces as well as your camshaft.
Viscosity:
First it should be noted that the SAE motor oil viscosity chart (J300) is different from the SAE gear oil
chart (J306). A SAE 40 motor oil has approximately the same viscosity as one of the thinner SAE 90
gear oils, while the SAE 50 Motor oil is similar in viscosity to the thicker SAE 90 gear oils.
Viscosity has nothing to do with API Gear Oil classification (GL-4, GL-5, etc.). Some manual
transmissions specify an ATF (Automatic Transmission Fluid), others a SAE 75W-80 (almost the same
viscosity as the ATF), others a 75W-85, 75W-90 or 80W-90. Some specify a SAE 50 motor oil or SAE
50 CAT TO-4 transmission oil. The oil viscosity should be chosen according to the manufacturer's
recommendations for the temperatures where you will drive.
• If it is too thick (viscous) it will not displace fast enough from the synchronizers and will heat
up your transmission and cause hard shifts. It will also fail to flow properly in the needle
bearings or other tight spaces.
• If it is too thin it will not provide the hydrodynamic lubrication that is required between gears
and in the bearings or bushings.
If we look at the service manual for the Corvair, the one I have from 1960 recommends SAE 80 Gear
oil. While I do not have a SAE J306 viscosity chart earlier than the 1996 update, in the graph below we
can see what those viscosity limits were in 1996, with the blue being the range for SAE 80 and red
being the range for SAE 90. What this means is that any given brand had to stay within that range for
that weight of oil.
The Difference between GL-4 and GL-5 gear oils 5 of 12
You will note a huge range is possible between different brands within each range. In the chart on the
right-hand side you can see that the 80W-90 gear oils on the market today are thinner than the thinnest
SAE 90. You could actually use a synthetic 75W-140 if you could find it in a GL-4.
SAE 80W-90 or 85W-90 oils are often referred to as multigrade oils. This is not true. They have no
polymers to modify their viscosity. They are simply SAE 90 oils with a normal (95 to 105) viscosity
index where the low temperature properties either meet the 80W or 85W specification. So, an 80W-90
is at the low end of the SAE 90, while the 85W-90 is at the high end of the range for a SAE 90.
From personal experience and that of several friends who have tried them, I recommend staying away
from the 85W-90 in Corvairs and most other cars, since that puts it at the high end of the 90 scale. You
will notice a harder shift for the first few shifts of the day.
Recommendations
In general, you should use your manual. Nobody knows the vehicle more than the people who put it
together. The exceptions are cars like the Corvair where oils have changed dramatically since the
manuals were printed. There are other exceptions where those who write manuals have no idea how a
transmission works and are guided by wrong information from oil salespeople.
You need to realize that an oil with GL-4/GL-5 on the label is a GL-5. It is not appropriate for
synchronized transmissions.
The Difference between GL-4 and GL-5 gear oils 6 of 12
For the Corvair:
• Considering that most Corvairs have seen a lot of miles, there is probably some wear in the
transmission, so we could look at the higher viscosities within the recommendations unless it
has been rebuilt.
• This is a car that was produced long before any of the oils that are on the market today. My car
was a perfect example of what happens if you do not have any EP additives. The teeth on the
synchronizers were in excellent condition. But the rest of the transmission had severe signs of
wear. (See picture below)
• Too much additive may reduce the wear on gears, needle bearings, and shafts in certain
conditions, but will wear out your synchronizers. You need to look for a GL-4 oil that does not
include GL-5 in its label, even though it looks good, even though it claims GL-4/GL-5 on the
label. The Corvair differential is well built with parts much bigger than those of many cars
today. Those gears can carry the power of the car. You can see in the following picture of a
Toyota synchronizer how the brass synchronizer has worn so much that the entire ring bottoms
out and no longer grabs.
The Difference between GL-4 and GL-5 gear oils 7 of 12
• For many climates, the SAE 80W-90 is the best viscosity for the Corvair. But there are synthetic
products available that cover that full range with a SAE 75W-90 rating. This would be even
better especially in cooler climates. The trick in this formulation is a very high viscosity index
in the synthetic base oil. See the chart at the end of this article to see how a few typical oils
react to different temperatures. You should note that you might need to shift below the -20ºC
shown as a starting point in these graphs. In this case, the synthetic oil is your best bet. Most
manual automotive transmissions will run between 30ºC and 50ºC in normal operation. I have
been using 75W-90 GL-4 for at least a year and have much better shifts. Morning temperatures
here are normally in the 65ºF to 75ºF range.
• Corvairs with automatic transmissions: This is much simpler. Just use a good Dexron III in the
transmission and a good GL-5 in the differential, adding the LSD additive if the oil
manufacturer does not include it and if you have "positraction". They may or may not include
it. You have to read the label or spec sheet. As an example, I have
• 75W-80 GL-3 without LSD
• 75W-80 GL-4+ without LSD
• 75W-85 GL-4+ without LSD
• 75W-90 GL-4 with LSD and without
• 75W-90 GL-5 with LSD and without
• 80W-90 GL-4 with LSD and without
• 80W-90 GL-5 with LSD and without
• 75W-140 GL-5 Synthetic with and without LSD
• 85W-140 with and without LSD
The Difference between GL-4 and GL-5 gear oils 8 of 12
To confuse things a little more, we have to read the literature and sometimes consult with the
manufacturers. In looking for a few GL-4 products that would meet our needs, I identified Redline MT90
as a candidate, but then saw this on their website. I
questioned them and received this response.
"In your Corvair manual transaxle I would recommend the 75W90NS as a GL-5 type
gear oil was originally called for. A GL-4 gear oil is suitable for use in a zero or low
offset hypoid gear application, where extreme pressures of a high offset hypoid are
present a GL-5 gear oil is required. In your transaxle where high offset gears are not
present, a GL-4 gear oil could be used though we would recommend a GL-5 as called
for."
While he confirms that the Corvair does not have high offset hypoid gears ("In your transaxle where
high offset gears are not present"), he says he recommends his GL-5 product because the Corvair
originally recommended GL-5 ("a GL-5 type gear oil was originally called for"). There is a problem
with that statement: The GL categories are based on the ASTM STP 512 standards which were
originally developed in 1972, three years after the end of the production of the Corvair.
Here is a clarification from Lubrizol (one of the premier additive companies)
Summary
Just remember that GL-4 and GL-5 are gear oil ratings, not transmission oil ratings. Transmissions
have gears and synchronizers. These seemingly conflicting requirements must be met differently.
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.
What should you do if you cannot find a GL-4 that does not include GL-5 on its label? My next choice,
and one I almost did even though I have plenty of GL-4 80W-90, would be a SAE 50 oil that meets
CAT TO-4 specifications. My third choice would be a SAE 50 diesel motor oil of the highest API
classification I could find, preferably group II. As you will see on the graph below, the temperature
curve for a SAE 50 motor oil (or CAT transmission oil) and a SAE 80W-90 are very similar.
But we should not get carried away thinking we cannot find a GL-4 oil. There is plenty available in
75W-90. I get emails from all over the world, and we almost always come up with an answer.
What should you do if you've put a bigger engine in the Corvair or dramatically increased the HP? I
would use a synthetic GL-4 oil. If I felt it was not enough (gut feeling, stubbornness, etc.), I would
send it away for analysis, then use a GL-5 for the same period of time and analyze it. If the GL-4 is not
sufficient protection, it will show up in iron particles in the sample. The GL-5 might reduce the iron
The Difference between GL-4 and GL-5 gear oils 9 of 12
wear, but you can see for yourself how much copper increases. The only problem with this is the
sample base is not statistically valid. But it will give you more than a guess unless you have magnetic
plugs or magnets on your filter.
I have received comments from people who have used VW transaxles with 150 to 200 hp engines in
racing situations, where they say the synchronizers are expendable, but the gears are expensive and
hard to come by, so GL-5 is better. It will make for harder shifts, but if you are going to quadruple the
torque, you may be better off that way. It is a personal decision.
Here is a simple explanation of the problem from Nissan:
It is interesting to note in this explanation by Lubrizol how the new SAE J2360 (replaces the GL-5
rating) is explained:
"SAE J2360 is a global quality standard specified by many North American OEMs and
by growing numbers elsewhere in the world. The rigorous approval requirements,
including controlled field testing and independent committee review, ensure that products
approved under the SAE J2360 Standard meet the very highest demands of axles and
non-synchronized manual transmissions." (emphasis added).
The important part of that statement for us is the last part: "and non-synchronized transmissions",
since our transaxles are synchronized.
Here is a synchronizer that has been worn by GL-5 oil.
You will note that there are no longer any teeth on the
brass, completely worn or "peeled" away
The Difference between GL-4 and GL-5 gear oils 10 of 12
Here is a chart that shows the behavior of several transmission oils at start-up temperatures.
The Difference between GL-4 and GL-5 gear oils 11 of 12
Here are those same oils in normal operating temperatures once everything has warmed up.
Product possibilities
I hate to call these recommendations, but will list what I can of products that I know of and that are
available in the US. As always, this is as of this writing, and all information is gathered from the
Internet. Local availability will vary.
First lets remember that the details are in the spec sheets. Some brands make it hard to find the
information.
The Difference between GL-4 and GL-5 gear oils 12 of 12
I can applaud Mystic Oil's clarification when they start their spec sheet this way (although later in the
sheet they only mention the various GL classifications. Note how they say "and non-synchronized
manual transmissions."
Texaco, on the other hand, does not mention this
limitation, although it is the same. They just don't
mention transmissions at all in their 80W-90 gear
oil. They leave it up to the consumer to realize that
transmissions don't use normal gear oils (as such).
The list:
My list is a short one. If you want me to add something I can look at it if you send me a link. I've been
looking and don't see much. These are listed in alphabetical order.
• Amsoil Synthetic manual Transmission and Transaxle Gear Lube 75W-90 GL-4
• Citgo Citgear Standard XD 75W-90 GL-4
• Pennzoil Gearplus 80W-90 GL-4
• Pennzoil Synthetic 75W-90 GL-4 (from the spec sheet, the best overall viscosity curve)
• Quaker State Multi-purpose Gear Lubricant 80W-90 GL-4
• Redline MT90 is a good possibility, although their
web page has this disclaimer. Note my
observations on page 6.
• Shell Spirax G SAE 90 GL-4 (I do not recommend this due to it's extremely high low
temperature viscosity.)
• Shell Spirax GX 80W-90 GL-4 (I do not recommend this due to it's low high temperature
viscosity)
• Chevron had a product called Chevron Manual Transaxle oil that was excellent, but I cannot
find it except in clearance sites. I don't know if it has been replaced.
In general I would not use a 75W-90 in a Corvair transmission unless it was synthetic, but there are
some very good GL-4 Synthetic 75W-90 oils in the market for Mercedes, Volvo and Mack truck and
bus transmissions that would be acceptable, especially in colder climates. Look for one where the
viscosity at 100ºC is 15 cSt or above.

I hope this clears up some of the confusion and avoids transmission damage.
If you have additional questions, feel free to send them to me at oil@asboman.com
If you have not read the report on motor oils, you can find it here:
Selection of the right motor oil for flat tappet engines.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

SHOdded

A quick comparison by Blackstone of the Amsoil and BND offerings, thanks to AnotherGreen Fusion
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

SHOdded

2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

SHOdded

https://royalmfg.com/calciumsulfonate/

QuoteOVERBASED CALCIUM SULFONATE GREASES FOR EXTREME ENVIRONMENT
By: Dr. Anoop Kumar, Steve Humphreys and Bill Mallory
Royal Mfg Co. LP
Published by: Greasetech India Vol XIV, No. 3 January  - 1 March 31, 2012

Abstract:

There are number of grease thickeners available for making lubricating greases. However, each one of them possesses its own strengths and weaknesses.

Calcium sulfonate complex greases, not new to the industry, are known for over six decades and have been improved over times by various people to make suitable grease for different applications. This class of grease is known for having excellent high temperature, extreme pressure and rust protection characteristics. The down side of its performance is poor pumpability, poor low temperature properties and higher cost compared to lithium greases.

In general, the art in preparing this class of greases involves converting liquid overbased calcium sulfonate to grease containing calcite particles. The degree of conversion to calcite form can greatly influence the properties of the finished grease and therefore the art lies how best one controls the process parameters and incorporate the other performance enhancing ingredients during processing stage.

The worldwide volume for calcium sulfonate greases is increased from 1.2 % in 2005 to 1.4 % in 2010. In North America, its volume increased significantly from 3.8 % in 2005 to 5.4 % in 2010, where in India it's merely about 0.8 %. In North America by virtue of its characteristics these greases are gaining more popularity over others and are gradi !ally becoming true multi-purpose greases.

Besides having robust multi-purpose calcium sulfonate greases, the authors have recently developed some innovative specialty sulfonate greases as a result of perfecting unique process parameters and optimized compositions. One of the products developed is a super heavy duty grease for extreme pressure conditions that exhibit 800 kg weld load and 70 lbs TimkenOKload. Other grease covered in this paper is grease for marine applications having excellent rust protection and passing 1000 hrs salt fog test and the third one is arctic grease for extreme low temperature characteristics having mobility of 18 gm / minutes at - 40°C. The details of those performance characteristics will be covered in this paper.

Key Words: Lubricating grease, Calcium sulfonate, Weld load, Penetration

Introduction

Over based calcium sulfonate greases, also popularly known as sulfonate greases, are not new to the industry as it appears and were patented as early as in 1940's. One of the reasons for development of this class of greases appears to be the efforts to improve the high temperature capabilities of calcium greases.

Calcium base greases are known to possess excellent water resistance and low temperature properties but poor in high temperature capabilities.

Zimmer et al, patented sulfonate base grease having good water resistance and having melting point over 400 °F (204 °C) (1,2) . Sproule and Pattenden ( 3 ) reported that grease prepared using combination of high and low molecular weight sulfonates as thickening agent provide grease with higher drop point.

McMillen in 1960's patented calcium sulfonate greases having dropping point over 500 °F (260 °C). Since then, the basic principle of making gelled overbased calcium sulfonate greases using liquid over based calcium sulfonate with total base number (TBN) ranging from 300 to 500 remains practically unchanged. In a general process, highly overbased sulfonate is mixed with base oil and treated with acid, lime and suitable promoters where amorphous  calcium carbonate is converted into desired crystalline calcite form followed by removal of promoters and water from the mixture ( 5 ). During the process, amorphous calcium carbonate can readily be converted either to calcite (desired form) or vaterite, an undesired form of calcium carbonate.

The process is highly sensitive to the processing parameters and ingredients used and therefore, end use properties greatly depend upon how the grease is processed. Muir et al, reported high performance calcium borate modified calcium sulfonate complex grease exhibited dropppoint point over 570 °F  (299 LC) and excellent other performance characteristics (6).

Conventional overbased calcium sulfonate greases reported, in general, are known to possess high dropping point, good water resistance and rust protection properties, and superior inherent extreme pressure properties. The down side of these greases is found to be inferior low temperature and limited pumpability due to high thickener content used to make these greases. Due to their superior characteristics over other grease_ especially over most popular lithium greases, its volumes worldwide are on gradual increase. NLGI 2010 worldwide market survey indicates that volumes of calcium sulfonate greases has increased from 1.2 % in 2005 to 1.4 % in 2010 (7). These greases are gaining more popularity in North America with its volume increase from 3.8 % in 2005 to 5.4 `)/0 in 2010. By virtue of greater awareness and unique characteristics, this class of greases has started to gain importance in Indian industry as well, though the volumes are just merely 0.8 % in 2010. A wide variety of overbased calcium greases are reported in literature and are commercially available with different claims. However, the properties of this grease are greatly dependent upon the process parameters, reacting components and the type of additives used to enhance the properties. The conventional additives used in other greases like lithiums do not necessarily provide the similar effect in calcium sulfonate greases. Royal Mfg Co LP has been making overbased calcium sulfonate greases for decades and the formulae and compositions have been customized and perfected many times so as to meet most severe application requirements of the industry. We have recently developed 3 new products, one super heavy duty grease having 800 kg weld load, second one for marine applications passing over 1000 hrs in salt fog test and the third one with extreme low temperature properties exhibiting mobility of 18 gm/minutes at - 40 °C as per US steel mobility test. The performance characteristics of these greases have been covered in this paper.

Experimental

The base oils used in preparing greases are commercially available mineral and/or synthetic oils of different viscosities. The mineral oils used are either neat or blend of paraffinic and / or naphthenic oils. The overbased calcium sulfonate thickeners were prepared using 400 TBN sulfonate. The greases reported in this paper are commercially manufactured in oil heated counter rotating kettles having capacity of about 5 Tons per batch and were either milled through Charlotte mill or APV Gaulin homogenizer. The greases were tested as per standard ASTM / IP test methods. The grease mobility has been tested as per US Steel mobility test. The salt spray test was tested as per ASTM B 117 test method.

Results and Discussion Development of Heavy Duty Calcium Sulfonate Grease

There are different kinds of greases being regularly used in automotive and industrial applications. In general, extreme pressure (EP) greases used in automotive wheel bearing, chassis, disc brake, universal joints, fifth wheel etc are either lithium/ lithium complex, aluminum complex , and calcium sulfonate greases meeting NLGI GC-LB specifications. Similar kind of greases can also be used in industrial applications with minor modifications for moderate operating conditions. Typical properties of commercially marketed grease fo: medium to high speed bearings are tabulated in Table -1.

Such greases are normally made with group I or naphthenic base oils and fall in viscosity grade ranging VG 150-220. Typically these greases possess weld load of the range 250-400 kg and Timken OK load to the tune of 40-50 lbs where calcium sulfonate greases possess little higher Timken load of about 50 lbs or more. The water washout for these greases typically is less than 15 % wt @ 79 °C. However, there are some more severe applications like off high-way applications, construction and mining equipment which require much better extreme pressure and heavy load carrying characteristics and other properties compared to typical NLGI GC-LB or multipurpose grease. The EP greases used in such severe industrial applications like in metal processing industry, mining, construction, drilling, paper mill, are typically lithium/lithium complex, aluminum complex, clay base and calcium sulfonate greases and general characteristics of those greases are tabulated in Table-2. The industrial applications where the loads are much heavier and bearing sizes sometime are larger, VG 320-460 oil based greases are recommended and are doped with higher amount of EP additives to meet stringent requirement of the industry. On the other hand calcium sulfonate greases do not require much additives to meet these requirements. Interestingly, it is difficult to further boost the EP characteristics of the calcium sulfonate grease. •As there are a number of manufactures and suppliers of these classes of greases, there is increasing emphasis from the market to develop some niche products having heavy duty grease capable of handling not only extreme heavy duty and shock load conditions but also stand out providing competitive advantage. In view of this, we have recently developed a heavy duty greases specially designed for heavy duty industrial operations like in mining, steel and construction industries. The comparative test data of this grease are tabulated in Table-3. The data indicate that the new heavy duty grease exhibit superior performance characteristics compared to conventional sulfonate greases available in the market. The conventional calcium sulfonate greases available in the market exhibit weld load of about 400 to 500 kg range where as new developed grease has indicated maximum possible weld i.e., 800 kg tested as per ASTM D 2596 Method without adding molybdenum disulphide or graphite. Similarly the Timken OK load for conventional greases ranges from 45-55 lbs where as the new grease has exhibited much superior Timken OK load of 70 lbs. This superior performance could possibly be attributed due to the combination of factors. One of them is optimizing the process parameter in such a way where total conversion amorphous calcium carbonate to crystalline calcite takes place minimizing the formation of undesirable vaterite form. Greases having dominant calcite form of calcium carbonate are reported to possess better EP properties as compared to the one having predominant vaterite form of calcium carbonate. Calcite fish like platelet structure is reported to help in better film formation and thus provide superior EP properties whereas carbonate particles in vaterite are oriented perpendicularly [8]. On the other hand, conventional EP additives like sulphur-phosphorous and/or antimony-zinc type additives typically used in lithium greases do not perform well in sulfonate greases and therefore it is rather difficult to further boost EP properties of calcium sulfonate grease. Additionally, we have identified a synergistic combination of additives that help to achieve highest weld load of 800 kg and very high Timken of 70 lbs.  comparatively indicate that new heavy duty calcium sulfonate grease exhibit much superior EP properties in terms of weld load with respect to its other counterpart. Besides this, this new greases exhibited very good pumpability characteristics at normal and below normal temperatures. As per US Steel mobility test (USS DM 43), this grease indicated mobility of 13.2 gm/minutes at — 18 °C (0 °F) and 3.2 gm/minutes at —30 °C (-20 °F)  which is considered good and comparable to our conventional grease having base oil viscosity of VG 220. This makes this grease better suitable for applications where greases are pumped through centralized lubrication systems especially in steel mills and mining.

Superior Calcium Sulfonate Grease for Marine Applications

In applications like marine and off shore drilling, grease exposed to either directly or indirectly to salt water and therefore rusting of equipments is pretty common. For such applications having sultry environment, lubrication of bearings, gears and wire ropes requires grease having resistance to water washout, water spray off and resistance to corrosion in salt water environment. In such applications, calcium sulfonate greases are an obvious choice, having inherent properties of rust inhibitions. The water washout characteristics are tested by ASTM D 1264 method and water spray off by ASTM D 4049 test method. For testing anti-rusting properties for marine applications, salt fog spray test (as per ASTM B117) has emerged to be better than other rust tests. Some of the customers are demanding greases meeting salt fog spray test data as high as 1000 hrs. This stringent test requirement is not met through lithium or even a majority aluminum complex greases. If calcium sulfonate grease is not formulated carefully, it may not meet this stringent requirement. We have developed grease specifically for marine application meeting this requirement and test data are tabulated in Table-4. This grease exhibited excellent mechanical stability; very good extreme pressure properties in terms of 620 kg weld load and 65 lbs Timken OK load and excellent rust protection properties as tested by ASTM D 1743 test and salt spray test ASTM B 117. This grease passes rust test (ASTM D 1743). In salt spray test this grease exhibited excellent performance in terms of passing over 1000 hrs salt spray test where other greases failed early. This grease might have run more hrs but test was discontinued after completing target 1000 hrs. Other grease which is also calcium sulfonate base grease in same viscosity range failed after 360 hrs thus providing the superior performance. The reasons for this superior performance are not completely understood however, it could possibly be attributed due to interaction of polar heads of overbased calcium sulfonate with the other ingredients / additives.

Arctic Calcium Sulfonate Grease for Cold Climate Applications

Calcium sulfonate greases are known to be inferior in pumpability due to higher thickener used to make NLGI 2 grease compared to other greases like lithium complex and aluminum complex greases. Calcium sulfonate complex greases, on the other hand, have proved to advantageous over lithium complex and aluminum complex greases in certain applications like mining and steel due to better extreme pressure and natural rust protection properties. Aluminum complex greases are also known for better water resistant properties and thus the candidate for mining and drilling operation. However, the more popular greases in these applications are either lithium or lithium complex greases so far and for transition, the choice lies between either aluminum complex or calcium sulfonate complex grease. Calcium sulfonate complex earns more points due to better compatibility with lithium and lithium complex greases over aluminum complex greases. There are some applications in mining and drilling operations like up in Canada, China and some European countries where the temperatures can be very low specially in winter and the greases are required to pump as low as — 40 °C/°F . Therefore the challenge lies to make a grease having good pumapability at such low temperatures and many of the calcium sulfonate available in the market do not meet this requirement. The greases used in these applications are generally synthetic oil based lithium, calcium and or aluminum complex greases. In some cases there are two grades of greases used like summer grade in NLGI 2 consistency and winter grade in NLGI 1 grade. Synthetic greases do fill this void to an extent but their high cost is the limiting factor. We have recently developed arctic calcium sulfonate grease in semi-synthetic base oil, meeting cold climate requirements. The test data are tabulated in Table-5. Table -5 indicates that the grease in NLGI 2 consistency exhibited excellent mechanical stability only 11 units change in 100,000 double strokes penetration and a high drop point of + 277 °C. Weld load of 620 kg and Timken OK load of 60 lbs indicates that this grease encompasses excellent extreme pressure properties as well. This grease also possesses good rust preventive properties as indicated by ASTM D 1743 test. US steel mobility test data conducted at -18°C and -40 °C/°F indicate its mobility 140 gm/min at -18°C and 18 gm / min at -40 °C/°F. In general, the customer requirement for such applications is minimum 4 gm/min mobility at - 40 °C/°F and therefore this arctic grease has exhibited much superior data. This may primarily be attributed to the fact that we have carefully optimized and perfected our manufacturing process and control in such a way that uses reduce amount of thickener to make NLGI 2 grease and also the viscometrics are adjusted in such a way that help us to meet this stringent low temperature requirement simultaneously while retaining the other properties.

Conclusions

Overbased calcium sulfonate greases constitute significant volume of worldwide grease market and its volume is considerably increasing in North America. Calcium sulfonate greases are known to possess superior high temperature, extreme pressure and rust protection properties as compared to other greases. The drawback associated with this class of greases is limited pumapability especially at low temperatures. These greases in different base oil viscosities and grades are being regularly marketed by different manufacturers / marketers across the globe. In order to further enhance the scope of this important class of greases in critical applications areas, we have successfully developed three greases. The first grease developed exhibited very high extreme pressure properties as indicated by 800 kg weld load and 70 lbs Timken. The second grease has been intended for humid environment specially in marine and off shore drilling operations. This grease has exhibited excellent test results in salt fog test and successfully passed over 1000 test hrs. The third grease was developed for very cold climate and tested as per US Steel mobility test at -18 °C and -40 °C and test result indicate its mobility of 140 gm/minute and 18 gm/minutes respectively which is considered pretty good for calcium sulfonate greases.

Acknowledgements

Authors are thankfully to The Lubrizol Corporation for help in testing the grease samples and also to the Royal, Tulsa grease plant for providing the grease samples.

References

1. Zimmer, J.C., Duncan, G.W., "Grease compositions" US Patent No. 2444970 , July 1948 .

2. Zimmer, J.C., Duncan, G.W., "Grease compositions" US Patent No. 23082, January 1949.

3. Sproule, L.W. and Pattenden, W.C., "Sulfonate base lubricating grease" US Patent No. 2535101, December 1950.

4. McMillen, R.L., "Basic metal-containing thickened oil compositions" US Patent No. 3242079 March 1966.

5. Fish, G., and Ward, W.C., " Calcium sulfonate greases revisited" presented at 78th NLGI Annual Meeting , Desert Palm, CA, USA, June 11-14, 2011

6. Muir, R. and Blokhuis, W, " High performance calcium borate modified overbased calcium sulfonate complex greases" US Patent No. 4560489, December , 1985

7. NLGI , USA annual grease market survey , 2010

8. Macwood, W. and Muir , R., " calcium s
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