First off, there is no need for Hy-Tran in a WD or WD45.
Forward most compartment/drain is the hyd & belt pulley drive area. Uses regular hyd oil, doesn't need hy-tran as no heavy loads here. The filler for this area is the one on left side, by clutch pedal, with a dipstick under the cap. Don't remember how much it holds.
Second, third, & fourth drain are PTO, hand clutch, trans, & diff, all connected. Use regular gl 1 or gl 5, 80W-90, or even 80W-140. IIRC takes 17 quarts. Two filler plugs, 3/4 square heads along left side of trans/diff case. Hint- if you don'thave an 8 point socket for square headed bolts or pipe plugs, use a 12 point socket 1/8 larger than the square: 5/8 12 pt fits 1/2 sq, 7/8 12 point fits 3/4 sq, etc. Can fill completely using one fill plug, but takes a long time for oil to flow past divider, quicker to fill both plugs.
Caution- PTO housing is the lowest point, any water from condensation will collect here. If it freezes it will break & push the bottom right off.
Might not need to buy new oil. If not excess water in it, filter it thru one of those red gas funnels, with the brass screen. I have one that the screen is fine enuff that it will let gas thru, but not water.
I'm aware you knew all this, but might be handy for some of the newbies out there. How's that for a disclaimer?