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- Nov 11, 2013
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The wear looks like mechanical wear not so much yellow metal being eaten by evil compounds.
From the original post:
Photo below shows the black stained worn syncro on the right.
![Synthetic GL5 gear oil - it is bad for brass? Synthetic GL5 gear oil - it is bad for brass?](https://scontent.fden3-1.fna.fbcdn.net/v/t1.0-9/136981599_10219859582299594_3260360575500349767_o.jpg?_nc_cat=103&ccb=2&_nc_sid=0debeb&_nc_ohc=8ti4iasDYuQAX8gtNW8&_nc_ht=scontent.fden3-1.fna&oh=3e8a8d9cd96752524e6926c015c3e754&oe=6023D78B)
"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 the softer metal."