Help needed - Cincinnati Hydromatic milling machine

Hello,
I recently started helping out in a very old shop with a neglected Cincinnati Hydromatic flat bed mill.
We use it to do a lot of gang-milling and I would like to get it running better. It is possible this machine was purchased new and has been here its whole life.

The hydraulic system has started acting up (stumbling when traversing and cutters stopping when under heavy load). I am sure it *badly* needs a flush 'n fill of the hydraulic oil and hopefully there is a strainer that can be located and cleaned. Not sure what is the correct oil, and what needs to be opened to find a strainer.

The serial number on the bed is 1B2P1L 612 - There is also a plate that says "Machine Size 2-24 PL". If anyone has any info on this machine and maintenance experience they would be willing to share, please post to this thread or PM me.

Thank You !
-Scott

The Serial no, 2B2P1L is label as a 2 -12 and 2 -24 plain auto mill, ER model .1L is 1942. First check the oil Level. Then check the pressure (225 psi ). If the machine sets a lot, it may just have a lot of dirt and varnish in the system. The machine has two punps, One main pump with a filter and auxilary pump. Look for a bell housing for a pressure reducing near the filter. Some have strainers in the oil tank, not sure if yours has them. Fine where the oil reservoir is and the filter is near by. Pictures would help.

Thank You !
Here is a photo of the machine.
You can see the filler on the front, and the oil level window below the feed lever, just not sure where to get at a filter.

-Scott