You use Dextron in the hydrostatic transmission and 90w gear oil in the BGB and axle gear case. Fill to bottom of street elbow on each or the dipstick on BGB if so equipped.
Phil
"They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty."
The gear oil goes in the bevel gear box. That is right underneath the seat support in the front (that horizontal bar that is welded across the frame). Drain it, then refill until the oil (80/90wt) just touches the bottom of the dipstick (when dropped in, not screwed down).
The hydro fill I am thinking you have a Vickers, and on those I don't know. On a later model with a Sunstrand I can tell you.