In a message dated 96-03-30 10:50:56 EST, ui775@freenet.victoria.bc.ca
(Alistair Bell) writes:

>
>Dennis, your comment "GL-5 or better" implies that GL-5 is a superior 
>lubricant compared to GL-4. I thought that the difference was that GL-5 
>has additives that may be corrosive to VW syncromesh rings (they are made 
>out of brass or some such alloy?). GL-4 is recomended in the VW (and 
>BMW325) owner's manual for the transmission,  and GL-5 
>for the differential (where applicable).
>
>Have you seen any trannies that have failed syncros and you can attribute 
>the failure to GL-5 lubrication?
>
>nit-pickingly yours,
>
>

GL-5 is a better drade of lubricant and GL-6 is now becoming available.  The
problem was that the GL-5 eliminates friction better than the GL-4 and VW was
concerned I guess that thier syncro design would not work properly with the
improved lubricant.  Instead of testing thier transaxles with the improved
additive package or redesigning them, they just decided to keep GL-4 as the
standard.  In fact, in the automatics, GL-5 is recomended for the final
drives.  As for the brass parts being corroded by gear oils,  this was
aproblem when the extreme pressure aditive packages contained sulfur.
 Remember that gear oil smell of years ago.  Sulfur addditives are hardly
used now and this is not a concern in an automotive gearbox.  Use the GL-5 or
6 and your gears will love you.  Synthetics should also be considered.  The
extra money is cheap insurance for your expensive gearbox.
Dennis.