John deere 3320 cavitation fluid related?

[radios1]

Could it be the wrong dipstick? I was having trouble with mine at lower RPMs but the hydro was at the lower hash mark on the dipstick, so I figured one quart low, but close enough. Then I filled it to the full mark but it actually took a gallon to move that half inch, then all was good after that. So when the manual says it takes x gallons, I don't believe it. But you went to one gallon over so that should negate that scenario.

even well designed aircraft use accumulators to smooth out the pulsations from cavitation.. it works very well..

 

[oldnslo]

Does this model have the filter on the inlet of the pump as well as a screen?

 

[Justjake450]

Does this model have the filter on the inlet of the pump as well as a screen?

Yes it has the filter on the bottom by the suction line and the inline screen

 

[Trainpilot]

If the 3320 has the same hydraulic system as the 4520, I have some answers. Our 4520 has a 2 circuit hydraulic pump, which is fed from a cast iron manifold that connects to the top of the pump with an o-ring for each section. This is fed from the sump. The rear circuit on our tractor feeds the steering and the hydraulics for the clutch/shuttle circuit. The rear o-ring leaks air under suction. Air into the hydraulic pump can cause chattering, surging, and noise. Too much air, it loses prime and doesn't operate. A plugged strainer might increase the tendency for this to occur. I have fought this problem on two previous occasions and am facing it again. This time I may try to machine the manifold so that the rear o-ring is pushed more tightly agains the housings. I'll post results soon. There should be some kind of TSB and fix for this problem if it is common.