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Final Drive Losing Oil Komatsu D31PX21 Bulldozer

Discussion in 'Dozers' started by Noland, Jan 31, 2019.

  1. Noland

    Noland Member

    Jan 31, 2019
    Brandon MS
    I have a Komatsu D31PX21 Bulldozer that recently noticed the final drive was grinding a little and has gradually gotten loader. When I checked the oil in the gear case it was completely dry and had what looked to black dirt inside the gear case. Refilled with oil... ran it, then changed the oil again. Did this a few times to flush as much dirt out as possible. After running the machine a few more days we checked the oil again and the gear case was completely dry again. So we refilled it, ran it a day and checked it again and it had lost about half a gallon. Can't not find any leaks behind the sprocket. Then noticed today the hydraulic oil was contaminated and black.

    Can gear oil from the case leak into main hydraulic system?

    Any help would be appreciated!
  2. John C.

    John C. Senior Member

    Jun 11, 2007
    Machinery & Equipment Appraiser
    I can't think of a way that final drive oil can get in the hydraulic system. It is possible for it to get into the transmission though. Sounds like you will be doing to gear work pretty soon.
    rondig and Vetech63 like this.
  3. rondig

    rondig Senior Member

    Jul 24, 2013
    fort macleod alberta
    Oh oh..sounds like major work is coming your way...sorry about your luck..sounds like main shaft seal leaking into trans...