Working on a 544G John Deere Loader that will not move in forward or reverse and the bucket controls do not work (no up, down, curl in or curl out.) Unit does articulate (this is a separate hydraulic pump) Drive shaft from engine to transmission is spinning. Driveshaft from transmission to gear front box is not spinning. Backed off parking brake and driveshaft still does not spin. I'm guessing fluid isn't passing through the pressure reducing valve manifold due to bad wiring/bad solenoids. Does anyone have information on what solenoid is for what? And what powers/grounds is needed to open the valve to allow hydraulic pressure to controls?
You said the machine does articulate because it runs off a separate hydraulic pump. Does the machine have the emergency secondary steering option to allow for articulation in this case ? Is the low brake pressure warning light on in the dashboard ?
I'll have to check if there is an emergency secondary steering option to allow for articulation. I believe I read this machine just ran off of a separate hydraulic pump. The low brake pressure warning light is on in the dash and flashing I believe. Owner of the machine said it has always done that and never had an issue.
There is a secondary steering indicator light and a stop signal on the dashboard that are illuminated plus a an audible alarm when the secondary steering is in operation so I am going to assume you do not have that option. The loader hydraulic pump feeds the steering system through a priority valve so it appears the loader hydraulic pump shaft is turning. The brake /pilot pump is bolted to the hydraulic pump. The brake/ pilot pump supplies oil to the park brake, the loader pilot system and the (differential lock if equipped). I assume the transmission is not going into gear because the transmission controller is not seeing the park brake pressure switch on the pressure reducing valve closing. All that said ,I suspect the brake / plot pump has failed. It’s a closed center pump so you can deadhead the pump with test guage to check the pressure or can also check the standby pressure at the reducing valve.Brake/ plot pump standby pressure spec is 2400 psi. . Check your messages.