The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Bill Conquest on December 11, 2007, 12:23:23 AM
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Hi - I just read on the Benchmark web site that any gl-5 gear oil is corrosive to pre-'92 trns/final drives, to use gl-4 only. Any thoughts on this? I use royal purple syn 75 - 90, is this stuff o.k. ? Aloha, Bill Conquest
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What's the link? I've been using GL-5s since 1993 with no ill effect. 80W90 in oct - april and 85W140 april - oct. I won't mention the brand. I seem to recall that this was for the original spec GL-5 but todays GL-5's are not harmful to the bronzes (????) What does the Snowbum say? Time for some more reading (again).
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This is another one of those myth's that was right at one time, like not putting a battery on a concrete floor, or it will get discharged.
I think it was probably 30-40 years ago, some gear lubes had a lot of sulphur in them, and I guess with water contamination and age, you could get sulphuric acid to form in the mixture, and that attacked bronze / brass materials.
Use a name brand high quality oil, and you won't have any problems.
If you were wondering about the battery myth, it was true when battery cases were made of wood, when was the last time you saw a wood cased battery at the local auto parts store ?
So that shows you how long that myth has been around !!!
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Well, I know it sounded questionable, but I read it on Craig Vechoriks's Bench Mark Works BMW site last night & just wondered...