JD 4440 Powershift Hydraulic Problems

miraclefarms

New User
Needing some diagnostic help for my JD 4440 powershift. Got some water in my system back in March, thanks to some help from a neighbor. Have changed the oil and filters 3 times. Just put a new front pump on. No change. Tractor does perfectly with all hydraulics for about an hour. After it heats up, the hyd. seat, steering, SCV's and lift stop responding or get very slow. Won't pick up disk and can feel a chatter in the system. Tractor still shifts fine when heated up. When tractor cools down, all back to normal for another hour or so. Tried removing the filters just to see if they were getting plugged. Screen has been cleaned too. No change. Any ideas? Thanks!!
 

More than likely there's a large internal hyd leak. One needs to perform diagnostics to determine why hyd stop operating correctly when the oil gets hot. Procure a laser thermometer and check temp of each hyd component when hyd oil is hot then note the differences in temp. if there is any.. Many hyd pumps have been replaced to determine hyd pump wasn't at fault. Has hyd pressures ever been checked? I will suggest to never operate tractor without having hyd filters in place.
 

Thanks, Tx Jim. The pressure hasn't been checked. I'll look into your suggestions. I wish I knew more about troubleshooting the system.
 

You could buy a JD 4440 tech manual as it contains a lot of info.

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