Galion 503G 1801

Working on my Galion 503G number 1801. The seal is leaking on the front of the hydraulic pump. This unit does not have power steering. It looks like there is some sort of adapter between the pump and transmission. Anyone have any info on the pumps? All I can find info on is the newer models with power steering. Also does anyone know did the models go 503G 503A 503L? Thanks View attachment 222719