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      03-02-2013, 11:27 PM   #7
5soko
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Drives: M5
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Quote:
Originally Posted by jjw2331 View Post
My dealer puts in FM booster diff oil regardless of noise. I had it in my diff after my 1200 mile service, again after a seal was replaced, and again after I got a replacement diff for a strange clunk that was not normal. Never did I complain about a grind, but I still got the FM booster fluid.

I asked my dealer for bottles of diff oil to change my own fluid last year. They gave me three bottles of 75w-140 diff fluid with FM booster. I know castrol saf-xj (now known as castrol syntrax limited slip) is the older fluid or what comes in our cars when brand new. So I asked for it and the parts guy said FM booster is only fluid we use on M differentials. I guess its the new standard fluid. But thats just from my experience.
Thanks for that I appreciate it. Either way im gonna make sure that's what they use in my diff for my upcoming service!

Quote:
Originally Posted by Vic311 View Post
+1
Quote:
Originally Posted by Fen335i View Post
I used the OEM diff fluid w/FM booster as well on my last change. My goodness it's expensive...I might try an aftermarket high-end fluid next time. The OEM stuff is highway robbery...kind of like the 10-60 TWS oil! At least now Redline is making 10-60 now that is slightly cheaper.

Yea im gonna use the OEM stuff on this service aswell. I like to stick with the oem stuff. Just needed clearing up on what exactly and if the FM booster is the standard now. Thanks.
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