I always use Castrol 20-50 straight 50 if it's a leaker and some leak more than others. 10-30 in the primary and 50 in the tranny unless the tranny leaks then I use 90.

My 69 TR6C hardly leaked at all my 72 T120V leaked no matter what I did. My 66 TR6C was middle of the road as far as leaks go.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!