Got this lull 1044-54 the hose coming from pump 1 to mid inlet valve surges constantly all functions work properly no real sluggish issue or low power customer just dosent like the surging any ideas at 1st thought was relief valve but theirs 4 so can't isolate. Then got to wondering if it could be pump causing any ideas or checks thanks. Service manual dosent have diagnostic for this issue I attached picture of where hose comes in on valve
If it was me I'd pull the accumulator and have it checked for low charge pressure and leakage. eliminate that first. That's always the starting point. Then if there's still an issue you can start hunting it down. Also, the serial number of the machine will help with troubleshooting.
My 844C-42 which I got as a project did the same thing main boom up when I replaced the main tandem pump. It also was pulsing big time to return tank from front fork tilt frame tilt valve blocks. One of the many relief valves might be partially stuck open or you may need to re adjust pressure settings of each also which I did solved issue.
They older ones non electrical solenoids a lot of work tracing issues I pulled every control spool valve in main valve block as well checking seals and for stuck valves etc. You gotta go through whole system basically checking everything and relief valve pressure settings.