Posted for "Tracy Crook" <lors01@msn.com>:

It would be nice to have the ideal lubricant for each system but the down
side of separate systems is:  Separate Systems.  Twice the chance of failure
and twice the weight & complexity.  The synthetic oil in the engine system
is not ideal but it is lots better than the transmission fluid which the C6
planetary gears normally get.

And, if the engine oil system fails, you have more important things to worry
about than the gear drive not getting oil : )

There are a lot of other factors but short of time to go into them.

Tracy Crook