Copper Strip Tarnish Test: 10 Gear & Trans Fluids

[studegator]

when I click on the links, all I get is (404 -not found)

 

[ripcord]

Holy thread necromancy, Batman!

 

[studegator]

Found one from 2019 that works-
https://www.earthtools.com/pdf/yellow-metal-friendly-gear-oils-test-results1.pdf

 

[MolaKule]

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 5w30 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).

If you are looking for MTFs, here is a list of fluids that have both the proper metal inhibitors and friction modifiers:

Thread 'Updated List of MTFs'

May 30, 2024

Updated List of Manual Transmission Fluids Updated May 30th, 2025

NOTE: This list is only a “summary” list of MTFs available in the MTF Lubricant Market and only available in US auto parts stores and US Import outlets. It is not an endorsement nor a critique of any one fluid, nor is it implied that any one fluid will cure problems in MTs that have design problems or those that have excessive wear. Viscosities listed are at 100C and rounded up.

A.These MTL fluids are closest to a Kinematic Viscosity of 6.X cSt@100C (About the same viscosity as Dexron VI ATF) LV MTF's:

1. HPL Manual...

• MolaKule
• Replies: 0
• Forum: ATF, Differential, Trans, Brakes, P/S

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