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D8N leaking hyd oil into transmission

Discussion in 'Dozers' started by Alberta Cowman, Mar 19, 2020.

  1. Alberta Cowman

    Alberta Cowman Active Member

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    Hi guys.

    Last night my operator called that the hyd oil was low as it had cavitated when he was pushing up a pile. This is a D8N 9TC02252.

    It was fine in the morning and after seven hours it had lost 45 L. It was dark but we could see it dripping from a stump pan. The transmission oil was also over the full mark which was puzzling.

    This morning we dropped the pans and turns out the leak is from the diagnostic port on the lubrication supply line to the left side of the flywheel housing.

    Great this is an easy fix I thought for about 5 seconds before I realized it was leaking transmission oil.

    I have since come to the conclusion it is leaking hyd oil into the transmission and that this transmission oil leak is totally unrelated.

    Am I correct in thinking that the only places it could leak hyd oil into the transmission is either the hydraulic pump or the steering motor?

    Is there any way without bench testing the pump and steering motor to narrow it down which is the issue?

    All the hyd circuits are working fine otherwise.

    Thanks.
     
  2. MattR

    MattR Well-Known Member

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    I am not familiar with that machine, but it does sound consistent with a hyd pump seal to me.
     
  3. John C.

    John C. Senior Member

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    I believe you have the problem worked out pretty well. You probably need a service manual at this point if you have never had to remove either of those components.
     
  4. Alberta Cowman

    Alberta Cowman Active Member

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    Thanks guys.

    I do have a service manual.

    I pulled the pump and motor. A reman pump is $11,700 and a reman motor is $6800. It's a little more than I was expecting. Checked a few hyd shops and they're at least a 2-3 week turnaround.

    I've never opened up a piston pump or motor but figured why not now. Pulled the shaft seals and the motor one is as hard as a rock. No groove or wear on the shafts luckily. I picked up both seals, o rings and two drums of oil and am going to give that a try.

    I'm hoping that it's as simple as it seems.
     
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  5. John C.

    John C. Senior Member

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    Shaft seals usually leak because there is too much case drain going on. The end of the barrel rubs against a plate with the inlet and outlet ports in it. The leakage us usually in between those components when grooves get cut from trash or foreign material.
     
    56wrench and Alberta Cowman like this.
  6. MattR

    MattR Well-Known Member

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    I'd try that first too. Holy balls that's a lot of money.
     
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  7. Nige

    Nige Senior Member

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    The price of operating Big Yellow Iron......
    Work out the cost of 36 Reman engines @$250k a pop.....and that's before I get started on radiators, transmissions, difs, final drives, suspensions, hydraulic cylinders, and the 1001 other "minor" components on the trucks - That's 2 years planned overhaul budget just for the truck fleet.
     
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  8. MattR

    MattR Well-Known Member

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    Glad I operate a fleet of old crap nowadays. Yes they have costs too, but there are ways to cheapen things up. Plenty of used parts out there also. And they operated with a lot less of the "fancies" and tight tolerance components. Not as productive for sure but they get the job done. When one owns the other option, you're married to it. Not for me anymore. I once had $22,000 in monthly equipment payments when I had my large logging operations. That was no way to live in my opinion. But to each his own. I changed my life up about 12 yrs ago. I'm not rich but I have way more money in my pocket now. And I actually hunt, fish and atv ride with my kids again. None of which I did back then. "Too busy" working. And all the while God's time clock kept ticking. And you never know when "the boss" is going to punch out for us. Glad I opened my eyes.
     
    Last edited: Mar 21, 2020
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  9. Alberta Cowman

    Alberta Cowman Active Member

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    Well I think I lucked out this time.

    I replaced the shaft seals on the pump and steering motor. Filled the hyd oil and did a 4 hr job just across the road from the shop. Monitored the level and it rose 3/8" due to the oil warming up.

    Replaced the transmission oil and took it back to the field. Now it has over 20 hrs and hasn't leaked any oil.

    Seems to be cured so far.

    I looked through the service manual and didn't see a spec or procedure for checking case drain flow.
     
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  10. MattR

    MattR Well-Known Member

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    That's what we like to hear!
     
  11. Alberta Cowman

    Alberta Cowman Active Member

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    Yeah, me too. My Mrs wasn't really amused with the thought of having to drop another big chunk of change so soon.
     
  12. Nige

    Nige Senior Member

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    You need to give the tractor a name. I suggest Boris.

     
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  13. Alberta Cowman

    Alberta Cowman Active Member

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    Lol. I like that.

    I've taken to calling her Bertha and her little sister the D6C is Betty.
    image.jpeg
     
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  14. Queenslander

    Queenslander Senior Member

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    Do you have any pics of the work you are doing?
    We are in the cattle game here and are always raking and burning something.
     
  15. Alberta Cowman

    Alberta Cowman Active Member

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    Hi queenslander.

    We walk the trees down with the blade up a couple feet. Most of the stumps roll out of the ground with the tree. Mostly dealing with poplars, willows and some spruce or pine here. This is after walking it down.
    image.jpeg

    Next we pile with a brush rake. This gets all the logs and most of the bigger branches.
    image.png

    There's always some smaller branches, smaller 2-4" trees that don't break off at the ground, roots and broke off stumps left so we scrape it with the blade. Works best doing everything with some frost so you don't end up with as much soil in the piles. Don't have any pictures after scraping it as I'm in the shop and only head out to the field if there's a service needed.

    Usually two passes with a heavy towner breaking disk then a few with a wishek. Broadcast some oats for grazing and harrow it in.
    image.jpeg

    Burn the piles at the start of the next winter.
    image.jpeg

    Some guys use a KG blade and shear the trees off at ground level then pile.

    How do you clear brush down under?
     
  16. Nige

    Nige Senior Member

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    Like this ............. the bigger the material the bigger the tractors (and the anchor chain) that are required.

     
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  17. Queenslander

    Queenslander Senior Member

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    Exactly like that, although on a smaller scale.
    Our bushes are much the same...regrowth of similar size and density.
    We pull about half that width or a bit better with D6 size tractors.
    We rake it into piles and burn.
    The better soil country we run offsett discs over it and plant summer forage or improved pasture.
    The lighter soil country, we are just trying to keep the bushes off it.
    Left alone, eucalypt regrowth will come back like hairs on a cat’s back.
    We have a buggy to shoot Graslan pellets at anything that comes back after raking, which seems to be sorting them out pretty well.

    950H and D6R posing for some advertising last year.
    They work well as a team, dozer in the heavy going, loader scooting around the lighter stuff.
    051A837B-F2E3-4937-95AD-572CAA056062.jpeg
    Fiat-Allis 14C on burning duty this morning.
    0A7EF664-2E94-46BA-AB30-FA05D443E6A0.jpeg
     
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  18. Alberta Cowman

    Alberta Cowman Active Member

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    That is awesome. I'm always amazed at how fast the chaining goes. That looked great where they did it both ways.

    Up here there's quite a few bigger ~24" poplar, spruce or pine trees. They stop my D8N in its tracks and you have to tilt the blade and cut a few brace roots before you can push them over.

    I can't wrap my head around what size tractors it would take to pull a chain through a clump of those.
     
  19. Nige

    Nige Senior Member

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    Lot's of videos out there with larger trees in the using the same technique. Probably need something like a couple of D9's.
     
  20. Queenslander

    Queenslander Senior Member

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    It’s not as tough as you might think, especially in regrowth.
    The tractors in the video are doing it pretty easy, and our tractors would have no trouble at all, just go a little narrower.
    The 275 has obviously been seconded from elsewhere to do this pulling job.
    It has no scrub protection, tree pusher or drawbar...the chain is hooked to the centre ripper time, but in that light going it is handling it fine.
    Sounds like you need a tree pusher.
    Your D8 would waltz through those big trees then.
    Not the best photos, but we have two styles, one mounted on the trunnions, the other on the top of the blade.
    Pulling in big timber is all about technique.
    As you move through, the plan is to push on the bigger trees to loosen them, ideally to leave them leaning but still standing.
    When the chain passes over, it will ride up the tree and pull it to the ground.

    012A13A2-2A1E-4A54-B81B-CB64F80FD7EA.jpeg
    35A9C61B-0DE9-44F3-8126-4A8F8CD31CEF.jpeg
     
    Last edited: Mar 26, 2020