Alright, have the service manual in front of me now.

The very first thing that it says in the "Separator Drive Units" (Section 2) of the book is to describe how to test the system relief valve.

They want you to install a 300 psi gauge in the line between the electrical solenoid hydraulic valve and the separator clutch pack. After that they want you to run the combine for 10 minutes at high idle with the separator engaged to allow for the oil to warm up. Finally you're supposed to observe the reading on the gauge and make sure that it reads between 210 and 235 psi. If it doesn't, replace the relief valve and test it again. If the pressures still are not correct it's necessary to inspect the pump.

It says to refer to section 5, page 5-58 for more info. When you go there it describes how to check the charge pressure (using 15-147A charging kit which I don't have) to see if the pressure is between 90 and 110 psi. I did get a chance to look at the accumulator. It looks like it has a guard installed on it to prevent someone from trying to air it up maybe? Anyways, it was difficult to see, but it looks almost like something you could hook a regular air chuck up to so maybe if I remove the guard I can test the pressure without the kit.

Anyways, I was wondering if there is a flow test that I should be able to do in addition to these things. Thanks.