2002 770-3 hyundai wheel loader

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This topic contains 7 replies, has 5 voices, and was last updated by  Joseph 1 year, 4 months ago.

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  • #25734 Reply


    loader will not shift from reverse to forward or forward to reverse when it does work it works fine shift control is new and transmision solenoids are new

    #28307 Reply


    hi we deals in used and new parts of caterpillar, cummins, komatsu, detroit diesel, waukesha, dorman,jembacher if any one need any used or new parts please contact me

    #28311 Reply

    I don’t have any experience with Hyundai machines, but maybe I can still contribute a few diagnostic ideas. Do you have a laptop available for connecting to the machine’s data link? If so, you can monitor the transmission solenoid currents to ensure they are being energized. You can also just use a multimeter to backprobe the trans. solenoids and verify that the solenoids are getting power when the problem occurs. You replaced the solenoids but you could still have an intermittent open circuit in the harness that creates a fault condition. Perform electrical continuity checks on the input circuits between the transmission control lever and the transmission control module to verify the integrity of your harness. Do you have any transmission related fault codes present? Is there a fault indicator or alarm on? I’ve seen a loose ground strap between the cab and frame cause a similiar problem. Are there transmission pressure taps, that you can connect a pressure guage to, in order to monitor your direction and speed clutch operation when the problem occurs?

    When the problem occurs, does the display on your instrument panel show forward or reverse in response to the control lever position or does the display readout indicate neutral regardless of where the transmission control lever is? Does changing your transmission speed range selection (2F, 3F, 4F) make any difference?

    Have you checked your transmission screen for clutch debris? Does the transmission work fine when the trans. oil is cold and then start having problems when the transmission oil is at operating temp? Is transmission overheating?

    #28312 Reply


    thank’s for your response,the loader works really well when it works it might go for hours then when you shift it in to foward it won’t move sometimes if you shut the machine off for a few seconds it will start working sometimes it won’t sometimes you go back the next day it works fine all day in testing there is power on reverse coil all the time.thank you

    #28313 Reply

    Jim Owen

    ElectronExciter is giving you very good advice. But something else has come to mind you may want to explore if necessary.

    It does sound to me that you may have a continuity problem with the wires.

    Wires can become broken because of repeated bending in place. When this occurs, there is no visible evidence of a broken wire.

    If, however, the insulation was cracked or probed with a test tool, resulting corrosion can cause it to lose continuity. If this happens, you will see a swollen wire insulation, and if you examine that point, you may find a greenish powder, indicating the copper wire breaking down.

    To diagnose both of these occurrences: when the unit is operational, perform a tug test on the trans shift wires, ( a 5 pound, steady pull) may cause the wire to open, and lose continuity. When you find the right area, the trans may lose it’s ability to shift.

    It’s possible that you may visibly see the individual wire stretch.

    Wire breakage may occur when the wires are not adequately supported, and vibration causes the wires to work back and forth, OR, in places where the wires are supported too well and are made to flex repeatedly at the same spot.

    Good luck, and make sure you come back and tell what you found.

    #39190 Reply

    Gene graham

    I have the simular proublems with my hyundai 757 – 9 wheel loader can anyone suggestions

    #39229 Reply


    Hello Graham,

    I’d assume the gear selector with harness is somehow faulty.
    Guess, there is a ZF tranny with TC fitted. Does the display show the right direction?


    #48389 Reply


    The Hyundai wheel loader operates fine just for ten minutes for forward and reverse gears but would neither go reverse nor go forward after ten minutes please I need your advice

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