Copper Strip Tarnish Test: 10 Gear & Trans Fluids

pjf

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The Copper Strip Tarnish Test (ASTM D130-10) is a standard test of a lubricant to indicate how corrosive it is to copper alloys that may be in a transmission.

My restored 1989 Suzuki Sidekick has brass synchromesh transmission components that may be vulnerable to additives found in many GL5 lubricants. As a result, my owner's manual specifies a GL4 75W-90 or a GL4 80W-90 lubricant for the manual transmission and transfer case.

Lubricants that are "yellow metal friendly" are hard to find. I perused through data sheets and called lubricant manufacturers to find copper strip tarnish test results for their products. Those lubricants that I found test results for are in the table below.
Code:


M/T FLUID & GEAR OIL SAE API CLASSIFICATION



Amsoil Long Life FGR 75W-90 GL5 1B Dark Orange

Amsoil Severe Gr SVG 75W-90 GL5 1B Dark Orange

Amsoil M/T Fluid MTF 5W-30 1A Light Orange

Amsoil MT & Gear MTG 75W-90 GL4 1B Dark Orange

Citgo Citgear Std XD 75W-90 GL4 1B Dark Orange

Delo Gear Lubric ESI 80W-90 GL5 2A Claret Red

Delo Trans Fluid ESI 50W 2A Claret Red

Red Line MT-90 75W-90 GL4 1A Light Orange

Red Line NS Gear Oil 75W-90 GL5 1B Dark Orange

Red Line 75W90 GL-5 75W-90 GL5 1B Dark Orange

A brief description of the test can be found here: description D-130. The classification scale ranges from 1A (least corrosive) to 4C (most corrosive).
 
Why not research some more readily available GL-5 rated gear lubes such as the common Valvoline 75w-90 and 80w-90?
 
Originally Posted By: JRed
Why not research some more readily available GL-5 rated gear lubes such as the common Valvoline 75w-90 and 80w-90?

After posting the above table in a Suzuki forum, one of the moderators brought to my attention "A Study of Automotive Gear Lubes" on the Amsoil website (http://www.synthetic-oil-tech.com/Gear Lube White Paper.pdf).

On page 17 are ASTM D130 results for 14 gear lubes including Valvoline High Performance (80W-90) and Valvoline SynPower (75W-90). Both are classified as "1B."

I'm not sure how Amsoil got some of these results. I had called Pennzoil, Quaker State and Shell. Their support desks told me that they had no ASTM D130 information. I did not contact Valvoline.

We now have Copper Strip Tarnish Test results for 22 gear lubricants (10 + 14 - 2 overlap = 22).

Feel free to contribute by checking product data sheets or calling product technical support lines.
 
Originally Posted By: Colt45ws
Wow, Im surprised Delo ESI is so hard on copper. Interesting.

I never got a clean answer from Chevron Tech Support on the amount of sulfur in its Delo ESI lubricants. This prompted me to send samples of the two Delo ESI lubricants to Wear Check, which provides sulfur & boron content in its elemental analysis.

Unfortunately, after 9 days the lab still has not received the samples from USPS. If someone has sulfur content analysis of the ESI lubricants, please post them before I order more sample kits.
 
Here's the updated list of 22 gear & transmission fluids that includes data from the Amsoil paper (www.synthetic-oil-tech.com/Gear%20Lube%20White%20Paper.pdf):
Code:


M/T FLUID & GEAR OIL WEIGHT API CLASSIFICATION



Amsoil Long Life FGR 75W-90 GL5 1B Dark Orange

Amsoil Severe Gr SVG 75W-90 GL5 1B Dark Orange

Amsoil M/T Fluid MTF 5W-30 1A Light Orange

Amsoil MT & Gear MTG 75W-90 GL4 1B Dark Orange

Castrol Hypoy C 80W-90 GL5 1B Dark Orange

Castrol SYNTEC 75W-90 GL5 1B Dark Orange

Citgo Citgear Std XD 75W-90 GL4 1B Dark Orange

Delo Gear Lubric ESI 80W-90 GL5 2A Claret Red

Delo Trans Fluid ESI 50W 2A Claret Red

GM Synthetic Axle 75W-90 GL5 1B Dark Orange

Lucas 75/90 Synthetic 75W-90 GL5 4B Graphite Blk

Mobil 1 Synthetic 75W-90 GL5 1B Dark Orange

Mopar Synthetic

w/Mopar LS additive 75W-90 GL5 4A Trans Black

Pennzoil Gearplus 80W-90 GL5 1B Dark Orange

Pennzoil Synthetic 75W-90 GL5 1B Dark Orange

Red Line MT-90 75W-90 GL4 1A Light Orange

Red Line NS Gear Oil 75W-90 GL5 1B Dark Orange

Red Line 75W90 GL-5 75W-90 GL5 1B Dark Orange

Royal Purple Max-Gear 75W-90 GL5 4A Trans Black

Torco SGO Synthetic

w/Torco Type G LS add 75W-90 GL5 1B Dark Orange

Valvoline High Perf 80W-90 GL5 1B Dark Orange

Valvoline SynPower 75W-90 GL5 1B Dark Orange
 
Note the ASTM D130 test coupons never showed any corrosion, only tarnishing, except for the Lucas, MOPAR LS additive and the RP. But most of those lubes are primarily differential lubricants, not manual transmission lubricants. And how many modern differentials use brass components?

Also notice the copper strip used for testing is pure copper, not the brass copper alloys used in transmissions. which are more resistant to corrosion.

Your brass synchros will wear out long before any of the sulfur corrosively attacks them.

You are forgetting the fact that gear lubes contain metal deactivators, rust inhibitors and TAN buffers to inhibit any copper alloy attack.

I have torn apart quite a few manual trannys and have never seen any tarninishing of the brass synchros, with one exception. This exception was a manual tranny from a farm truck with 180,000 miles on it and the fluid had never been changed.

Which leads me to my final point: Change fluids between 30,000 and 50,000 miles to replenish original base oil viscosity and additives.

I think you're making a mountain out of a molehill.
 
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Originally Posted By: MolaKule
I think you're making a mountain out of a molehill.

...except for the Lucas, MOPAR LS additive and the RP.
 
So, with the exception of RL MT90 and AMSOIL MTF (rated 1A and both GL4) any of the other brands rated 1B should be A-OK for a manual transmission?

i.e., RL's NS Gear Oil and their 70W-90 GL5 s/b OK as well?

Thanks!
 
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Yes, a 1A or a 1B rating indicates a "yellow-metal friendly" transmission oil. An oil can be trusted to be "yellow-metal friendly" if it adheres to GL-4 standards. On the other hand, a GL-5 oil has to be tested to ensure that it passes the ASTM D-130 copper corrosion test if you want to use it in an older transmission.
Originally Posted By: MolaKule

I think you're making a mountain out of a molehill.

Of the 14 GL-5 gear oils in this study (http://www.goodsenseoil.com/G2457-GearOilWhitePaper.pdf), 3 failed the copper corrosion test. This means that the failure rate was 21% for this series of GL-5 oils.

Most car owners ignore the type of oil that mechanics place in their vehicles. You are in this forum because you care about the oil that you place in your transmission. If you have a classic car with yellow metals, do make it a point to use either a GL-4 oil or a GL-5 oil that passes the copper corrosion test.
 
Originally Posted By: pjf
Yes, a 1A or a 1B rating indicates a "yellow-metal friendly" transmission oil. An oil can be trusted to be "yellow-metal friendly" if it adheres to GL-4 standards. On the other hand, a GL-5 oil has to be tested to ensure that it passes the ASTM D-130 copper corrosion test if you want to use it in an older transmission.
Originally Posted By: MolaKule

I think you're making a mountain out of a molehill.

Of the 14 GL-5 gear oils in this study (http://www.goodsenseoil.com/G2457-GearOilWhitePaper.pdf), 3 failed the copper corrosion test. This means that the failure rate was 21% for this series of GL-5 oils.

Most car owners ignore the type of oil that mechanics place in their vehicles. You are in this forum because you care about the oil that you place in your transmission. If you have a classic car with yellow metals, do make it a point to use either a GL-4 oil or a GL-5 oil that passes the copper corrosion test.


I agree with MolaKule that this is largely a case of making a mountain out of a mole hill. Consider that some Military Spec I ran across lists not only 1a and 1b but also 2a as "copper friendly." Where does pjf come up with Chevron Gear ESI as being bad for yellow metal when the Chevron product that rates 2a is just one category (of 12) on the ASTM D-130 away from 1b which he refers to as safe for yellow metals?

The Military is interested in this stuff (ATSM D-130) because they have equipment sitting around sometimes for decades. The real shocker of this AMSOIL survey (merely a marketing scheme) is the Royal Purple product that rates 4a. Shocking really for a product that claims it is "yellow metal friendly." 4a is 3rd from the worst possible. For those interested in facts and clarity, it appears the ASTM D-130 has the following classifications for copper corrosivity. From best to worst--
1a. 1b. 2a. 2b. 2c. 2d. 2e. 3a. 3b. 4a. 4b. 4c.
 
Originally Posted By: pjf
Yes, a 1A or a 1B rating indicates a "yellow-metal friendly" transmission oil. An oil can be trusted to be "yellow-metal friendly" if it adheres to GL-4 standards. On the other hand, a GL-5 oil has to be tested to ensure that it passes the ASTM D-130 copper corrosion test if you want to use it in an older transmission.
Originally Posted By: MolaKule

I think you're making a mountain out of a molehill.

Of the 14 GL-5 gear oils in this study (http://www.goodsenseoil.com/G2457-GearOilWhitePaper.pdf), 3 failed the copper corrosion test. This means that the failure rate was 21% for this series of GL-5 oils.

Most car owners ignore the type of oil that mechanics place in their vehicles. You are in this forum because you care about the oil that you place in your transmission. If you have a classic car with yellow metals, do make it a point to use either a GL-4 oil or a GL-5 oil that passes the copper corrosion test.



+1
Great guide.
 
Allison automatic for big truck . my suggestion : Mobil delvac1
Atf (the one allison authorize.its the most awsome yellow metal friendly oil period(any oil allison ATF authorize is awsome
 
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I wish that "goodsenseoil"

wasnt posted so much it could also be called.

"that amsoil marketing pdf"

But if we grant it "fact" status it can be an interesting read.
 
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So I contacted Mystik, and they said their JT-7 Extended Range Full Synthetic Gear Lubricant SAE 75W-90 is 1A. So we can add that to the list as well.

I also found these: https://www.earthtools.com/pdf/yellow-metal-friendly-gear-oils-test-results.pdf

Which has a few not on the above list. Like Shaeffer Supreme Gear Lube

If the corrosion test is only a few hours, I personally would aim for 1A only, since a vehicle is going to sit in the same gear oil for years. (But there are obviously other factors to consider as well).
 
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The most compelling reason for me to not use a GL5 in my Miata was that GL5's SUCKED when it came to shifting. They didn't allow the synchros to do their job properly and you ended up with crappy notchy shifting.

Not saying that there wasn't one out there that would have worked, but that box, in particular, was much happier with something formulated for a manual trans, in my case RL MT90.
 
Originally Posted By: Colt45ws
Wow, Im surprised Delo ESI is so hard on copper. Interesting.

I never got a clean answer from Chevron Tech Support on the amount of sulfur in its Delo ESI lubricants. This prompted me to send samples of the two Delo ESI lubricants to Wear Check, which provides sulfur & boron content in its elemental analysis.

Unfortunately, after 9 days the lab still has not received the samples from USPS. If someone has sulfur content analysis of the ESI lubricants, please post them before I order more sample kits.
We ran a fleet study that used 50w MT1, 80w90 GL5 ESI in gearboxes and 75w140 /80w90 ESI in drive axles in heavy trucks. High hours, severe duty cycles. Many yellow metal components Of different grades in the gearboxes, auxiliary oil coolers and planetary axles. Never any yellow metal degradation observed (was not the point of our study but was part of tear down analysis). As a side note, ESI was one of the few lubes to not get cooked (oxidized) from sustained sump temps over 250F. We were impressed.
 
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