There is no makers plate on it but it has the word 'Hurth' cast into its end plate.
It is sitting on the bell housing for a Perkins 4108 marine diesel.
It was removed from a Volvo MD21 marine diesel engine, it has no raw water cooling and has a forward gear reduction of just over 2:1.
I would like to know what model it is and if there is a workshop manual available?
What oil does it use, I think it had engine oil in it?