Hello. I am trying to make my hydraulic works, but I am not sure which hydraulic oil goes in this pump

I need hardyscheibe gelenkscheibe (if this is the right word for this part) for my 1050 tractor. When I drive it in 4th gear it makes lots of noise. My mechanic said it's this part fault. But he say I can drive it anyway.

Hello everyone
I can't speak Deutsch, so I hope you can speak English and understand me. So that, you can help me
I got 1050 as a gift. I used it for a while. I have use it's plower for snow, went in nearby forest and picked up some wood. I didn't use lawn mower yet (something is broken).
Now I have problem. It won't start.
I had magnetic starter and I broke unterbrecher and zundspule (short circuit or something broke it).
I bought those parts on ebay. They were on same tractor. New zundspule is from car. Now I don't know how to connect wires with them.
I never had similar tractors and I don't know much about dynamo starter or other parts.