2005 Dixon Hydro Gear IZT fluid change ? New Mower to me, maintenance questions.

[dirtyb115]

Hi all. I just picked up a 2005 Dixon Ram 50 at a price I could not pass up. Has the 22HP briggs motor on it and hydro gear IZT motors on each wheel. I dont have a manual, and the ones i found online never mention servicing these motors. Do i need to change the oil in them? If so, does anyone know the procedure and what oil to use? Thanks so much for any help!