Dave @ Red line says their 75W90 GL-5 gear oil does not affect yellow metals. Heres what he said in an email.
Thank you for contacting Red Line Oil, in the shared Sportster primary/transmission the 75W90 is recommended, a product that has been used extensively and performs well.
The 75W90 is the product we have have used for a number of years with very good results in Sportster/Buell transmissions, matching the viscosity and type fluid called for.
The 80W Motorcycle Gear Oil is a lower viscosity than called for, the ShockProof gear oils can due to their unique characteristics could cause sticking of the Harley clutches.
The 75W90 would be preferred and recommended over 80W Motorcycle Gear Oil in these applications.
There can be issues with some GL-5 gear oils in certain applications. Some can be corrosive to brass, bronze or copper, not an issue with our GL-5 gear oils, they don’t cause corrosion, pitting or metal removal. In a synchro equipped transmission the friction modifiers contained in many gear oils can make them too slippery, though not the case in a motorcycle transmission with dog rings.
So if you want the right viscosity and dont want to worry about it damaging anything, go with Redline http://www.redlineoil.com/product.aspx?pid=133&pcid=4
Thank you for contacting Red Line Oil, in the shared Sportster primary/transmission the 75W90 is recommended, a product that has been used extensively and performs well.
The 75W90 is the product we have have used for a number of years with very good results in Sportster/Buell transmissions, matching the viscosity and type fluid called for.
The 80W Motorcycle Gear Oil is a lower viscosity than called for, the ShockProof gear oils can due to their unique characteristics could cause sticking of the Harley clutches.
The 75W90 would be preferred and recommended over 80W Motorcycle Gear Oil in these applications.
There can be issues with some GL-5 gear oils in certain applications. Some can be corrosive to brass, bronze or copper, not an issue with our GL-5 gear oils, they don’t cause corrosion, pitting or metal removal. In a synchro equipped transmission the friction modifiers contained in many gear oils can make them too slippery, though not the case in a motorcycle transmission with dog rings.
So if you want the right viscosity and dont want to worry about it damaging anything, go with Redline http://www.redlineoil.com/product.aspx?pid=133&pcid=4
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