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).
 
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Why not research some more readily available GL-5 rated gear lubes such as the common Valvoline 75w-90 and 80w-90?
 

pjf

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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%20Lube%20White%20Paper.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.
 

pjf

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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.
 

pjf

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Colorado
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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
 

MolaKule

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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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pjf

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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.
 
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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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pjf

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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.
 
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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.
 
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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.
 
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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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