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**Furno68C20** · 02-14-2021, 11:14 PM

Got a sm420 that needs an oil change. I heard that gl-5 80w90 has additives that don’t mesh well with older brass internals of the gears. Is this true?

Any recommendations on the correct oil.
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02-14-2021, 11:14 PM	#1
Furno68C20 Senior Member Join Date: Mar 2019 Location: Somonauk IL Posts: 319	GL-4 or GL-5 80w90? Got a sm420 that needs an oil change. I heard that gl-5 80w90 has additives that don’t mesh well with older brass internals of the gears. Is this true? Any recommendations on the correct oil. Posted via Mobile Device