I've done the engine oil and the hydraulics. The dirt floor in my shed need to dry out some before I get to the gears.
There are TWO drain plugs on the oil pan, one on either side of the front driveshaft housing. I refilled with Shell Rotella-T 15W40. The oil breather filter is where I put the fresh oil in. Clean the filter in diesel fuel and set aside. The location of the fill point is very inconvenient, and the oil has to make two 90 degree turns to get in. It's very easy to overflow the fill neck if you pour too quickly. It gets heavy pouring that slow, so consider gallon containers or smaller.
One drain plug at the rear of the hydraulic reservior. When it's empty, open the hydraulic filter housing and check/clean the screen. Take care to get a good seal when you reassemble the housing, or you'll lose a lot of new hydraulic fluid as soon as the pump starts drawing from the reservior. Mine was clean, so I didn't flush. But you might want to draun the fluid through some cheesecloth or something. The amount of crud (or lack of) should help you make the flush determination. I refill with AW32 hydraulic fluid, it may also be marked as ISO32.
I also had to flush the fuel tank, it kept filling up the sediment bowl with crud. The fuel filter was badly in need of replacement too.
There are two 5 gal buckets of Shell Spirax HD 80W90 waiting for when conditions are right to change the gear oil. And I'll get to the cooling system in the spring.
//greg//