Hello I've just purchase a John deere grader 770A The machine starts and run with no issue in the morning however after few minutes or an hour of work and all hydraulic systems stop responding (Blade, steering Wheel, gear switch/shift) then we've to turn off the machine and wait for several minutes and turn back on the machine for all systems to respond again. And few minutes again back to the same issues all hydraulic systems stop responding(Blade, steering wheel, gear switch/shift) Any help or suggestion is highly appreciated fyi i've recently changed the hydraulic pump and the issue is still not fixed
Welcome to HEF Jack ! Complete machine serial number please. Oil levels good?
He Yes the oil levels are good...This is the serial number of the machine 008395 Fyi when all hydraulic system stops responding also the temperature gauge and Oil gauge drops to zero even the engine is still on...electrical issues????
I can’t think of an electrical issue that would cause the loss of hydraulics and transmission all at the same time. If you loose hydraulics and transmission at the same time ,I suspect the transmission charge pump is intermittently starving for oil. Check the overall condition of the transmission oil and also check the suction screen , item # 16 in the screenshot for plugging with debris / filings. https://partscatalog.deere.com/jdrc...earch/pgId/3940/partnumber/AR26375/callout/16 .
Thanks Dave the transmission oil conditions is good and the suction screen has no debris...is it normal that cooling system for the hydraulic pump is always cold even after running for 30 min???