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D5M Transmission Output Speed Sensor

Discussion in 'Dozers' started by bhtn, Sep 29, 2014.

  1. bhtn

    bhtn Member

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    Location:
    West Tennessee
    We're getting an active code on this dozer of 113-0673-02. I have the service manual for the machine and Cat has also pulled the codes previously so I know this is for the transmission output speed sensor. The dozer operates normally except that it won't always stay in 3rd gear. Once in 3rd it will sometimes drop back to 2nd. Can anyone tell me what I'm likely in for? I have heard that the transmission has to come out to change this sensor. I've also heard this is a common problem on this machine. I'll admit that we haven't read everything in the manual regarding this code yet. Just looking for some experience with this situation. Hopefully got our intermittent park brake issues solved with a new park brake solenoid so this is the last active code right now. Thanks, Billy
     
  2. Nige

    Nige Senior Member

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    Send me a PM With your email address and the machine Serial Number. I can forward you a procedure that will help you to determine exactly what is the root cause of your Diagnostic Code.

    specifically your Code is the #2 Transmission Speed Sensor giving "intermittent, erratic, or incorrect" data. Sounds to me like it could be a bad connection somewhere, however the possibility that the sensor is buggered also exists.
     
    Last edited: Sep 29, 2014
  3. lantraxco

    lantraxco Senior Member

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    Or you have a bearing going out, causing the distance between sensor and teeth to vary.... seen that happen though not on this particular machine.

    As Nige says, most likely a bad connection.
     
  4. bhtn

    bhtn Member

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    IMG-20141004-00172_zps1ec8da0a.jpg IMG-20141004-00173_zps3dbf8173.jpg

    I really appreciate all the help. Me and my friend started trying to test the connections according to the service manual and the service pages Nige was kind enough to send me. I need to be sure I'm in the right spot to test these wires. Is this the right connection for me to be testing the speed sensors? According to the book and diagram it should be. If this is the right connector then I can't figure out what the problem is. We're getting infinite resistance across each of the 4 sensors and I'm sure that isn't right because right now the dozer isn't showing any codes whatsoever. You normally have to run it a while before the speed sensor code even comes up. I'm hoping I have the wrong connector but can't seem to find the one I need. Any help would be appreciated.
     
  5. Bob/Ont

    Bob/Ont Senior Member

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    You probably have the right ones. Intermittent means it still works but throws a glitch now and then. Some service letters call for replacement and can be done from the back but it's a hard job. A scope on the sensor wire would tell you a lot when running.
    Later Bob
     
  6. Nige

    Nige Senior Member

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    Try blasting both of those connectors (male & female) with a good-quality aerosol electrical contact cleaner, apply some dieletric grease and re-attach the connector and tighten up the screwed connector well. Run the machine and see how it goes.

    The problem with the Diagnostic Code Troubleshooting procedure is that the Code has to be present (Active in other words) while you are trying to diagnose things. If it is not present then you're flogging a dead horse.
     
  7. trackdoc

    trackdoc Well-Known Member

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    If you have access to a small forklift you can pull the trans out in a few hours, change both sensors, check the internal harness and slip it back in.
    Be done in less than a day for a novice.
    Once you remove the draw bar, belly plate, half shafts and main drive shaft it's a pretty easy job.
    When your in there have a little look around for any trash inside the rear end incase you maybe have a bearing gone.
    Have you pulled the screens yet ? (magnetic and scavange )
    Have you checked the harness from the ECM to that connector at the transmission ?
    The harness under the floor of a dozer is exposed to a lot of heat, and can give trouble too.
     
  8. bhtn

    bhtn Member

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    Location:
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    Thanks. We will try putting the contact cleaner on them. We put it back together but it was dark so we didn't run it much. The pins and connectors looked REALLY good and clean. So you're saying the transmission speed sensor wires at that connector (transmission side) will show as open (infinite resistance) if there is no code present? Wasn't expecting that. The service manual says they should show 1200 ohms and basically they are OK if they do.
     
  9. bhtn

    bhtn Member

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    Location:
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    Thanks for the reply. We're trying to do the simple things first obviously. We really think it's a wiring problem because of the intermittent nature of the problem. No we haven't pulled the transmission screens. No we didn't check the harness yet because the procedure in the service manual is to ohm the sensors first and that's where we're stuck right now because I'm getting zero ohms at not only the problem sensor but all of them. I figure I'm surely doing something wrong. Yes I understand about the harness living in a tough environment. We pulled the seat looking for the right wiring connector and it was amazing how dirty it was up under there. We scraped and vacuumed most of it out while we were there. Thanks very much for the reply.

    Edit to add: We briefly looked at the procedure to pull the tranny and it didn't look "too" bad but for novices not having a CLUE what they're doing we hope it doesn't come to that. If it does, I'll be back looking for more help. :)