Yes the diff and trans use the same oil, we use 80-90 or so,they aren't picky. The final drives are separate so check those individually. Do not idle in neutral for long periods as the upper shafts won't oil unless in motion. If newer than a G keep a close eye on the double 60 chains, they are dog breath and will break and lock up the final drives. If you break one stop and fish it out then toss it and put in a new one, do not master link it consider it scrap. Lastly fish plate the blade arms right before the curve where it welds to the circle, it will break where the little stiffener welds between the arm and the circle. I know you only had one ques. but I want to pass on my experience on these machines. I have had these apart to the last bolt and know them well so if you need help fire away.