I have a JD 444E that we use for snow removal and last season the light for the "HST HYD Filter" came on intermittently. I replaced the filter, but I don't think it changed the intermittent frequency. Then later in the season the "HST Charge Pressure" light came on. Sometime in unison with the other light but not always. We also found that when the loader was in high speed mode, the "HST Charge Pressure" Light would not come on. Does anyone have any quick pointers to get me started? I can put a pressure gauge on, but I was looking for insight incase this was a common occurrence. For example, is there a pick up screen on there I should check first? Also, does anyone know if the filter light uses a differential pressure to read a restriction or is there a popoff valve with an indicator sensor/switch? Also, anyone have an idea why the Charge Pressure light goes away when in high speed mode? Thanks!
The filter switch should operate on a differential pressure, if I recall. As far as the charge pressure light being on only in low speed, pressure checks need to be made. That is a very complicated powertrain system. If this is something you are looking to tackle on your own, you will definitely need the Operation and Test Manual TM1421 and the Repair Manual TM1422, both found here .
Thank You, Yes, I have both of those manuals so I'll start digging into that. Seems like I always buy the stuff that's complicated... Thanks