Hi,
I just changed mine this week.
The way I read it is the rear end, and main tranmission all take hydraulic fluid.
The front diff takes 80/90 gear oil.
On the front end there are 3 drain plugs(one bottom center & one bottom at each end of the axle)
You refill at the plug located on the top right side of the axle. You fill until fluid runs out of the fluid level plug located approx in the middle of the center section. Takes aprox 2.5 gallons
They reccommend that you use teflon tape on the treads of the bottom plugs to prevent leaking.
The main transmisson has two or three drain plugs if I remember correctly. They each have magnets on them. Clean the metal slug from the magnets.
There is a lot of fluid in the main trans, approx 11 gallons so be ready.
To refill the main trans, you inject/pour the fluid into the inlet located at the rear of the tractor with the clear hose attached to it.(next to the dip stick)
The rear diff has a drain plug at the bottom end of each axle. The refill inlet is at the top of each axle end. The fill level checking plug is located at the rear of the diff housing about mid ways up. Just refill until fluid runs out of these level checking plugs. It takes approx 1.2 gallons for each side.
All said it took about 14 gallons of hydraulic fluid and 2.75 gallons of 80/90 gear oil.
Too bad we have to deal with such a hard to read and poorly written manual.
By now you would think that Montana would have produced a quality service manual for us to buy.
Ron