It is my intention to change the oil in the transmission and front
differential of my 86 Syncro.  Would synthetic oil be the preferred choice?
 If so, are there any distinctions between Redline and Castrol?

What weight would be appropriate for ambient temperatures that range from
-20 F in the winter to 95 F in the summer?  Would 75W/90 be best?

What is the capacity for the Syncro 094 transmission and front
differential?  (I have perused my Bentley without success.)

This oil change is scheduled for Monday, so quick responses would be most
helpful.

Budd Premack
86 Syncro, 84 Vanagon (soon to be for sale)
73 Super, 64 Bug (soon to be for sale)
Minneapolis, MN (Land of Sky-Blue Waters)