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621B still won't move right, oil question

Discussion in 'Wheel Loaders' started by asctc, Jan 1, 2016.

  1. asctc

    asctc Member

    Joined:
    Dec 19, 2015
    Messages:
    8
    Location:
    California
    Have a 621B that blew the transmission fuse and stopped moving. Took case service guy 3-days but they concluded it was the transmission control unit. Just replaced that and now it kind a moves but under a load (pushing snow) it stops again! It'll move in reverse, then starts to move forward again and stops again. Any ideas?

    Second question....service manual says transmission takes SAE 20W engine oil, it that the right fluid to use?
     
  2. GaryHoff

    GaryHoff Senior Member

    Joined:
    Feb 26, 2009
    Messages:
    750
    Occupation:
    Heavey Equipment Mechanic
    Location:
    Alberta, Canada
    Book calls for 10w30 from -4F to 104F (ambient air temp)
    20w from 14F to 104F
    30w from 14F to 122F

    Was it doing this before it blew the TCU (transmission control unit) fuse?
    I would check all of your ground wires. There is ground wires on the right side, by the cab connectors.
    Does it do this in all the gears?
     
  3. asctc

    asctc Member

    Joined:
    Dec 19, 2015
    Messages:
    8
    Location:
    California
    Loader was fine before fuse blew. After the transmission controller was replaced, and after adding two quarts of transmission oil it started moving again. It plowed fine for a couple of hours then suddenly forward stopped again, in all gears. There are no leaks.

    Reverse was still working until putting it in forward again, that caused reverse to stop working but then, after shifting back and forth reverse came back again. So basically I have no forward movement and intermittent reverse.

    After parking it I did notice air bubbles moving in the sight glass.

    Could sure use some ideas for fixing the, more storms on the way!
     
  4. backhoe1

    backhoe1 Well-Known Member

    Joined:
    Aug 24, 2007
    Messages:
    93
    Location:
    South Dakota
    I'd look very closely at the Forward - Neutral - Reverse shifter. They are known to cause problems and act intermittently
     
  5. d9gdon

    d9gdon Senior Member

    Joined:
    Feb 12, 2010
    Messages:
    1,385
    Location:
    central texas
    There are some ice cube shaped relays under the passenger side window that you access from the door below it on the outside. Swap them around and see if that fixes it. I had trouble with one that drove me nuts.
     
  6. GaryHoff

    GaryHoff Senior Member

    Joined:
    Feb 26, 2009
    Messages:
    750
    Occupation:
    Heavey Equipment Mechanic
    Location:
    Alberta, Canada
    As backhoe1 said, check your fnr shifter. You usually are able to shift forward/reverse using the joystick even with a bad fnr shifter. So if you can get all gears in forward using the joystick, it's likely the fnr lever. I have also seen the harness rub on the steering column.

    Some bubbles in the sight glass after shuting down/ initial start is normal. Just make sure your checking the transmission oil level with the machine running.
     
  7. asctc

    asctc Member

    Joined:
    Dec 19, 2015
    Messages:
    8
    Location:
    California
    The saga of this loader continues....after replacing the transmission controller it ran fine for a couple of hour then stop again. The transmission fuse was blown as was the new controller. We trucked it to the Case dealer in Reno that has been trying to figure it out for over a week.

    Finally.... they contacted Case engineering and have determined the wiring harness is bad. Good news is we (not the Case dealer) robbed electronic parts from the two bad controllers and now have a working one. Bad news is the local Case dealer says wiring harnesses for this machine (ser# JEE0056544) do not exist. Any ideas out there were we can find a wiring harness? Only 4500 hours on this well kept loader.
     
  8. GaryHoff

    GaryHoff Senior Member

    Joined:
    Feb 26, 2009
    Messages:
    750
    Occupation:
    Heavey Equipment Mechanic
    Location:
    Alberta, Canada
    Its possible the harness is bad. I would try and repair the faulty sections of the harness. Typical rub points in the harness (that would blow the tcu fuse) are around the steering column, and in the right joystick.

    If you cant see the harness damaged in those places, then your next best option would be to start removing the harness. You will probably find a damaged section upon removal.

    Its not a good idea to just keep sticking in new fuses and hoping they don't blow, as you can only blow so many before it takes out the tcu (as your dealer found out)
    The harness short needs to be found.

    You also need to remember that case does not fully support this age of machine any more. Case engineering will always say replace the harness if the short can not be found.