kubota grand L4740 weak charge pump, weak pto pressure, suction screen??

[jonsstihl]

Tried to adjust my pto pressure this week and found out I don't have enough range of adjustment in the valve to bring it up to spec. From the information I was able to grasp from the service manual. The pto pressure comes from the HST charge pump. I do not have the gauge and adapters necessary to check the charge pressure so it may have to go to the dealer for that adjustment.

The machine is new to me, 2013 so hstc-3 with 500 hrs on it and it is in pristine condition. does not appear to have been beaten at all. What are the chances that it is just out of adjustment and not the pump actually going out. Is the charge pump some type of modular setup that can be replaced without opening up the HST transmission. I realize they will most likely have to split the tractor but If I can avoid and HST replacement that would be great.

my other though is maybe debris in the system. Is there a suction screen somewhere on these machines like my old B7800 or did they switch to an external filter cartridge. My B7800 had two filters for the hydraulic system and a suction screen. This grand L 4740 appears to only have two external style cartridge filters.

thanks

 

[jonsstihl]

forgot to add that hydro fluid was changed by previous owner at 480 hrs and that all filters are Kubota OEM and I have no reason to believe that non kubota fluid was used. The other unknown is that the mid pto from my 4740 was swapped onto the new tractor the previous owner bought so the bottom plate has been installed with gasket sealer onto the tractor.

I bought it at 513 hrs and it has 542hrs now. they sure add up faster when it is actual time versus a cable operated tach like me B7800 that compensated for RPM.