This valve I'm using has an adjustable relief.
Yes you need that relief as well. It should be set to 1000 PSI for implement relief.
The 30-90 PSI relief is internal to the hydro and is located in the Pintle Assy Plate. All the return from the valve goes over this relief except for internal leakage of the high pressure side of the hydro.
I also upload another manual that will help you understand the hydro Description and Operation.
There are 3 Eaton manuals in the trans section, this being one of them, that you may want to down load and read.
Edited by ducky, November 20, 2016 - 01:05 PM.