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D6N SOLENOID THREE WIRES FRONT LOWER TRANSMISSION CASE

Discussion in 'Dozers' started by Philip S King, Jul 1, 2020.

  1. Philip S King

    Philip S King Well-Known Member

    Joined:
    Apr 24, 2019
    Messages:
    45
    Location:
    Alabama
    I have what appears to be a solenoid on the front lower transmission hosing. Accessed by the rear belly pan. The wires to this solenoid looking thing are missing their insulation near the harness plug that plugs into the solenoid connector. The damaged wires are on the harness side. Maybe the solenoid has failed, causing the wires to over heat? Found it while changing a cracked tube. Then after crawling out of the the space I found a dead mouse on the ground where I had just gotten up from. Wonder if they are realated ? I dont think so. Come to think about it. I think i was messing with the harness to get an idea of it's routing just prior .

    I need to know what the solenoid does and how it is wired. Any help or suggestions are appreciated.

    All the Best.
     
  2. Mark250

    Mark250 Senior Member

    Joined:
    Aug 30, 2015
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    1,081
    Occupation:
    heavy equipment technician
    Location:
    victoria,Australia
    I think you are looking at the transmission temp sensor
    but gee a serial number helps theer must be a million versions of the D6N
    upload_2020-7-1_17-17-49.png
     
  3. Nige

    Nige Senior Member

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    G..G..G..Granville...........!!
    Mouse (or any type of rodent for that matter) and missing harness insulaion - definitely related. Post a photo just to make sure what it is. A solenoid would have only two wires, with it having three it is likely a sensor of some sort as Mark said. If it is as you describe it will need the sensor replacing to fix it.

    It may pay you to do a thorough inspection and see whether or not he & his family had been nibbling anywhere else before his demise. Behind the dash panel or anywhere else where there are big bunches of wires would be a favourite.
    Create a signature line in your profile with the tractor S/N in it. That way you never forget when posting.
     
    Last edited: Jul 1, 2020
  4. Philip S King

    Philip S King Well-Known Member

    Joined:
    Apr 24, 2019
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    Location:
    Alabama
    CAT00D6NUALY02428
    I could not tell if the wires were chewed, melted or simply deteriorated . Should have got a picture. But yes that is the exact location and yes three wire. Mine however different. The piece protruding from.the same location is chromed or stainless metal and is larger. Thats why i thought it might be solenoid . Dint know temp sensor needed three wire.
     
  5. Philip S King

    Philip S King Well-Known Member

    Joined:
    Apr 24, 2019
    Messages:
    45
    Location:
    Alabama
    How do I test the sensor? And how do I repair the wire and test the wire . The damage is from the harness plug back at least 3 inches. I might be able to remove the plug pins. I wonder if cat will sell plug pins?
     
  6. Philip S King

    Philip S King Well-Known Member

    Joined:
    Apr 24, 2019
    Messages:
    45
    Location:
    Alabama
    I have removed the upper seat . Any trick to removing the base. I figure I can access the top of the trans housing after removing the seat. Right?
     
  7. Nige

    Nige Senior Member

    Joined:
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    3 wires as follows. Stabilized sensor power, sensor ground, & signal. Sensors like this one are powered from, and grounded back to, the ECM. Also that's where the signal from them goes. I'll send you the electrical schematic.

    upload_2020-7-1_12-9-47.png

    Yes they do. The pins are an 8T-8729 and cost about $1 each from Cat. Theoretically you need a $300 crimp tool to crimp the pins on to the wires - https://uk.rs-online.com/web/p/crim...VV-DtCh3OegriEAYYAiABEgL6kvD_BwE&gclsrc=aw.ds

    Personally I would try testing the sensor first. Leave everything connected and turn the machine key on. If you back-probe into the wiring plug marked in Red in the above diagram you should have 8v between Pins A & B. That would be between 709 Orange & G939 Pink. To test the sensor signal output you would need a multimeter that measures Duty Cycle. Do you have one of those..?