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CAT D4G Starts but does not move

Discussion in 'Dozers' started by JuanSpringCat, Feb 4, 2020.

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  1. JuanSpringCat

    JuanSpringCat New Member

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    The engine starts and blade moves, but park brake light is ON, it does not release. Can someone please share the electrical schematics of D4G (cat00d4gJ FDC00364). It does not move forward nor backward.
     
  2. Tyler d4c

    Tyler d4c Senior Member

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    If it's a hystat and quit all at once the plastic pump driver plate most likely failed
     
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  3. JuanSpringCat

    JuanSpringCat New Member

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    how do I know?
     
  4. JuanSpringCat

    JuanSpringCat New Member

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    Can someone please share the electrical schematics of D4G (cat00d4gJ FDC00364). It does not move forward nor backward.
     
  5. JuanSpringCat

    JuanSpringCat New Member

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    The engine starts and blade moves, but park brake light is ON, it does not release.
     
  6. Tyler d4c

    Tyler d4c Senior Member

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    Need to see if the pump is turning at all I'm not sure where to see it at all I'll do some research
     
  7. Mobiltech

    Mobiltech Senior Member

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    On a d5 i think you lose blade lift too when the coupler fails. Not sure if the d4 is the same.
     
  8. partsandservice

    partsandservice Senior Member

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    The hydraulic pump for blade is on the engine accessory drive. Blade functions will operate with striped drive plate. Park break light stays on because there is no brake pressure , because the drive pumps are not turning. Remove or slide forward the engine rather than drive pumps to avoid contaminating the drive system. That method has been mentioned on the HEF before and I use it as well.
     
    Last edited: Feb 5, 2020
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  9. Tyler d4c

    Tyler d4c Senior Member

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    You should still have the blade working as the pump is ran off the timing gears on the engine
     
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  10. Ronsii

    Ronsii Senior Member

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  11. Mbar

    Mbar Well-Known Member

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    Just dealt with This. Open door on right side of machine and check pressure on taps 3 and 4. Should see around 350 psi. That is front and rear charge pressure. If not charge pressure it’s the coupler. Like said above implement pump runs off from cover. Pull the cover and boot off the drive joystick. Had one rub the wires into and gave exact symptoms of a bad coupler. Make sure you have good working gauges when checking for pressure or it can Lead you down a bad path.
     
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  12. Nige

    Nige Senior Member

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    See post #11 above and follow it to the letter.
    I PM'd you the appropriate electrical schematic.
     
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  13. Tyler d4c

    Tyler d4c Senior Member

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    Small side note you may have to hook up the test lines on this 5g I have apart some are disconnected and capped so make sure there hooked up
     
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  14. Nige

    Nige Senior Member

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    +1. Why disconnect a leaking test line when you could probably fix it just as easily.?
     
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  15. RTSmith

    RTSmith Senior Member

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    I have also seen this same set of symptoms when a rat or squirrel chewed through some of my wiring harness......
     
  16. Tyler d4c

    Tyler d4c Senior Member

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    No clue that's how it was when it showed up here