Oil & Fuel oil level

[Blaquo]

Hi there,
I have bought second hand an old KUBOTA L 1501 and would like to check on the oil leve
Is The bolt marked with the red arrow the correct level fot this part of the transmission and incase oil needed to be added where do you pour it in?

 

[Agvg]

It's normal that the level plug is used for filling oil.

 

[Blaquo]

It's normal that the level plug is used for filling oil.

Then if used for filling how come oil gushes out when I unscrew the nut? Would it mean that there was too much oil inside?