Some of us have decided not to put Synthetic GL-5 transmission oil in our
transmissions as a result of information in the manual specifying GL-4 and
admonitions from tech heads at certain dealers urging that synthetic
transmission oil is too slippery and can hasten failure of our units. There
were some scarey posts on this topic about six months ago as I recall.

Thinking the dealer might have non-synthetic GL-4, I dropped over there. The
parts people said they had no GL-4. They said they had transmission fluid in
cans and that this transmission fluid is what they would normally use on my
car. They said the fluid costs $40 per quart but that the label on the can
does not specify whether the fluid is synthetic or what its GL rating is so
they don't know. They said it seemed like the fluid was really good stuff.
But added that since they didn't know what it was, they suggested I go to
Trak Auto (FLAPs) where the cans have labels. 

I did so and bought GL-5 house brand oil for $1.79 a quart. I could not find
any GL-4 fluid.

I made the reluctant assumption that it is OK to put GL-5 in the gearboxes
and that it is the "synthetic" part that could cause problems with being to
slippery (if such problem exists in the first place). 

Note that Dennis Haynes puts GL-5 synthetic into his gearbox and sees no ill
from this (also, the front diff in the syncro can take GL-5 synthetic).
___________________________________
Derek Drew                           New York, NY
drew@interport.net (main address for e-mail)
derekdrew@aol.com (alternate/backup, checked infrequently)