10 Speed Meritor Trans. No Shift from Low to High or back

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by DMVictor, Jun 3, 2019.

  1. DMVictor

    DMVictor Bobtail Member

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    Jun 3, 2019
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    2003 Volvo Day cab

    M11 Cummings Diesel Engine

    10 Speed Meritor Transmission ( electric over air ) MO-15G10A-M15



    Transmission rebuilt less then 10000 miles ago



    Truck will not shift Low range to High range or back without hitting the Shift Knob repeatedly ( palm of the hand ). The problem has gotten steadily worse as the weather has warmed up.



    REMEDIES I HAVE TRIED ….



    New shift knob ….. same issue.



    Tried testing the wire harness, not my specialty.



    Repeatedly drained my air tanks



    If the transmission cools down or in the morning it seams to shift fine. I go up a 9% grade empty to get to work and it wont shift unless I pound on the shift knob.



    Also if I am under a heavy load it seams to balk at shifting also.



    Love my truck at this point if it keeps giving me bills I am ready to hang it up FOREVER.
     
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  3. BoxCarKidd

    BoxCarKidd Road Train Member

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    Is that pounding, pushing the stick down? Maybe a worn shift tower causing an interlock problem?
     
  4. DMVictor

    DMVictor Bobtail Member

    5
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    Jun 3, 2019
    0
    Unknown

    I think it might be electrical / heat issue myself.
     
  5. Working2party

    Working2party Medium Load Member

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    Feb 10, 2018
    Kansas
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    When you hit the knob, is it while it’s in neutral? Could be the neutral switch. And after it starts can you get it to repeat itself while your parked?
     
  6. DMVictor

    DMVictor Bobtail Member

    5
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    Jun 3, 2019
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    Woohoo ! I found a cheap easy cure.

    All you need for this is a phillips head screw driver, a piece of wire and electricians tool.

    First take off the shrouding below the shift knob.

    Locate the 4 pin wires.

    Cut a 4 inch piece of wire off.

    strip both ends about 3/4 of a inch. ( I used 18 gauge wire )

    reduce the number of copper strands to 4 or 5 and twist together

    push one end of the wire into and besides the orange wire going into the connector, push the other end next to the white wire going into the connector.

    test your truck to see if it shifts into high and low range ..... if it does your done. electrical tape in place, button everything up and start rolling

    if not i wish you the best of luck.

    THIS IS A NEUTRAL SWITCH BYPASS. BE CAREFUL WHEN STARTING YOUR TRUCK AND MAKE SURE IT"S IN NEUTRAL !
     
  7. Working2party

    Working2party Medium Load Member

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    Kansas
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    You should know, that the neutral switch on that transmission tells the solenoid that transmission is in nuetral and it’s ok to shift from high to low or low to high. If your still in a gear and you flip the switch with it bypassed it will try to make the shift.

    So be ready for the change in operation with the nuetral SAFETY switch bypassed!!!
     
  8. kevinlangdon

    kevinlangdon Bobtail Member

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    Apr 10, 2020
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    What will happen if you run it this way? (Bypassed)
     
  9. kevinlangdon

    kevinlangdon Bobtail Member

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    Apr 10, 2020
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    Meaning....Is it SAFE to run it BYPASSED?
     
  10. BoxCarKidd

    BoxCarKidd Road Train Member

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    As long as you are the only one driving, don't get tired and screw up, sure.
    Make the money and fix it when you can.
     
  11. Volvoowner007

    Volvoowner007 Bobtail Member

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    Jun 8, 2018
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    Could you have not just replaced the neutral switch?
     
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