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D8 14a starter motor not engaging.

Discussion in 'Dozers' started by ZGrant231, Jul 31, 2021.

  1. ZGrant231

    ZGrant231 Well-Known Member

    Joined:
    Sep 11, 2017
    Messages:
    63
    Location:
    Oregon
    My d8 14a starter motor won't engage.
    It started acting up about the first day, only turning the engine over 50% the time. When it would act up. I would shut it off, go through starting sequence and it would engage and start just fine. Trying to limp it through the project, I delt with it until today.

    I removed covers for clutch and hi/low transmission, adjusted the clutch for the 100 lb snap in per operators manual.
    With a mirror and scope it looks like the trans is functioning normally, no broken, or chipped teeth, starting motor spins the gears all the way down to the lowest shaft in both hi/low.
    I thought it might be a flywheel tooth. I can grab the engine fan and turn the main engine over to many different spots with same result.

    What lies between the lower output shaft in the transmission and the flywheel, a pinion that is possibly stuck?

    Any advice is appreciated.
     

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  2. Old Magnet

    Old Magnet Senior Member

    Joined:
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    Messages:
    1,838
    Location:
    Corralitos, California
    Lots off stuff down there, could be a number of things. Might be as simple as a pinion latch adjustment or latch mechanism is worn out.
    D8-15A Pinion Adj.jpg
     
  3. ZGrant231

    ZGrant231 Well-Known Member

    Joined:
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    Location:
    Oregon
    I see there's a cover on the bottom of the transmission, is that where the pinnion latch adjustments are made?
     
  4. Old Magnet

    Old Magnet Senior Member

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    No, pinion latch access for adjustments are made by removing the transmission shift cover.
     
  5. hector gemme

    hector gemme Well-Known Member

    Joined:
    Mar 5, 2008
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    Location:
    Ste-Julie
    The shaft tread must be stripped or the pinion lock ring is out and you need to removed the starting engine assambly with transmission.
     
  6. ZGrant231

    ZGrant231 Well-Known Member

    Joined:
    Sep 11, 2017
    Messages:
    63
    Location:
    Oregon
    Well I found it...


    Pinnion gear was sitting in clutch housing when I pulled it.

    I'm assuming the six 3/8 bolts are supposed to be in these holes. That explains losing oil, probably into the clutch compartment. The o-ring seal behind the collar looks to be good and will seal.

    It appears the pinnion retaining washer has been brazed to somthing. I can not determine from service manuals. Is this a retaining bolt that is supposed to secure the gear to shaft? And what would cause this washer retention to come apart. I was operating at fairly extreme angles the days prior to finding the damage. Steep enough to keep an eye on the oil pressure guage if that might have anything to do with the damage.
     

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  7. Old Magnet

    Old Magnet Senior Member

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    1,838
    Location:
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    The 5H5909 shaft assembly had a washer head as an integral part of the shaft which then used a snap ring to retain the pinion. Apparently this unit has failed before and someone repaired (or attempted to repair) by brazing.
    Later versions changed to a bolt retained pinion and washer most likely due to common failures. The later versions also switched to a centrifugal release mechanism instead of the latches, also due to reliability issues. Your best bet is to obtain a new or good used 5H5909 shaft assembly. Nothing to do with your operating conditions, just time, wear and abuse of a weak link in the design.
     
    59 North likes this.
  8. hector gemme

    hector gemme Well-Known Member

    Joined:
    Mar 5, 2008
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    Location:
    Ste-Julie
    If the sleve bolts are gone the sleeme was loose and push on the pinion and the head shaft brook ,you need to change the shaft
     
  9. ZGrant231

    ZGrant231 Well-Known Member

    Joined:
    Sep 11, 2017
    Messages:
    63
    Location:
    Oregon
    Further assessment revealed a cracked braking cone and growling bearings. I went to a blown d7 pony I had for parts and it to had an almost worn through pinnion trust washer. With some used parts and great advice on here, it started under its own power again. Thank you everyone for the help.
     

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