Need education on multi viscosity gear oils

[Bruce O.]

I bought a 5gal pale of Schaeffers #167 75W-140 gear oil for the front and rear axles in my 99' Suburban with a G80 locking rear. The price works out to be around $8.50 per quart. What I know about this oil is that it has moly and that it is supposed use a superior base oil stock.

When you see a wide spanning multi viscosity gear oil like a 75W-140 does this mean that it is a synthetic but not necessairly a good quality synthetic?

I saw some very inexpensive multi viscosity gear oils at Walmart (their generic brand can't recall the name) that were in the 75W-130 range.

 

[MolaKule]

Search in the Interesting Articles portion of Science and Technology of Lubricants and Oil additives such as:

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000226#000002

You should find at leat three white papers on this topic.

 

[Bruce O.]

What should I search for in this forum? I tried multi viscosity and came up with nothing.

 

[mechtech]

Bruce - How about contacting the mfr. of the product?

 

[salesrep]

quote:

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When you see a wide spanning multi viscosity gear oil like a 75W-140 does this mean that it is a synthetic but not necessairly a good quality synthetic?

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No. It is Pao synthetic. You would be hard pressed to find a better 75-140.
http://www.schaefferoil.com/datapdf/167.pdf

 

[MolaKule]

Bruce,

Did you even read the technical data for the link I gave?

That would answer your question.

 

[TheFuror]

quote:

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Originally posted by MolaKule:
Bruce,

Did you even read the technical data for the link I gave?

That would answer your question.

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I read it and it was very illustrative.

Bob W.

But, the question I have is this: how important and/or relevant is the "Timken" load test?

Thanx

Bob W.

 

[MolaKule]

See:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=21;t=000071

The ASTM tests (and there are more than one of course) that use the Falex and Timken procedures
are tests to determine the relative load bearing and EP characteristis among various lubes.

 

[TheFuror]

quote:

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Originally posted by MolaKule:
See:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=21;t=000071

The ASTM tests (and there are more than one of course) that use the Falex and Timken procedures
are tests to determine the relative load bearing and EP characteristis among various lubes.

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Okay, so as I undersatand it, the test is similar to the four ball wear scar test in what and how it measures (relative efficacy of the add pack), as opposed to an objective measurement of true end performance. Close, at least?

Thanx

Bob W.

 

[MolaKule]

Right on Furor.

Once the IN-Lab tests are done and the add packs and base fluids adjusted to expected performance, the lube is then tested in a differential rig such as the FZG rig, or in actual fleet tests over as many different types of trannies and differentials as possible.

UOA's are then run against the VOA for wear metals and additive performance, the axles are taken down or inspected, and then the lubricant formulation is adjusted for final production.

 

[tdi-rick]

thanks for the link above Molakule.
I now know why the Neo 75w-90HD lube I used to use when I raced, and the PAO/ester euro Castrol lubes I now use in the Nissan Patrol and Land Rover stink just as badly as a mineral Castrol/Fuchs/whatever GL5 lube.

 

[MolaKule]

Most of the odor you smell is the smell of protection from the Sulfur and Phosphorus EP additives.