Synthetic ATF vs Mineral ATF

[Brandon Ong <ong2jr@xxxxxxxxxxxxxx>]

        A friend of mine enquired with the BMW dealership if he should use
synthetic ATF for his E36 325i with the ZF 5-speed autobox.  The BMW service
department said that synthetic ATF should NOT be used in the BMW slushboxes.
No reason was given but he only recommended using the regular mineral ATF,
as per BMW service instructions.  Now that puzzles me coz I always thought
Synthetic Lubricants are superior to the mineral oil and they exceed the
specs of regular mineral oil.  I must admit that my auto tranny, now with
the Mobil Synthetic ATF does not shift as smoothly as before, when it was
filled with Motul Mineral ATF.  Does anyone out there have any idea,
comments, recommendations?  Hope you all can shed some light.  Thanks a lot!  

Regards,
Brandon Ong
Singapore
95' 320i Cabrio - 5 Speed Auto

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