gear oil - GL-4 or GL-5?

[David Pertuz]

My former G20, now owned in California by a friend, is getting a new clutch
tomorrow. I was telling him some things to be aware of (to mention to the
mechanic, really, since he is not the faintest car person) and I cannot
remember whether GL-5 is OK for the trans in those cars. I remember that
the service manual calls for GL-4 - I'm certain this is correct. I also
remember that GL-5 may be bad for the synchros in the long run, but I'm not
certain of that. I also remember that when I replaced the engine in the car
years ago I absolutely could not find GL-4 anywhere, and ended up using
Castroil Hypoid C, which was GL-5 and obviously worked OK since it was in
there for ~80k miles and it always shifted great. Is the correct weight of
GL-5 oil OK for the trans? I might have put Redline MT90 in there a few
years ago (I can't remember!) but this is not a situation where anyone is
going to be putting Redline in there.

thanks,
David
Chicago
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.se-r-list.org/pipermail/se-r/attachments/20120313/ce0b85e2/attachment.html