Crawler Loader/Dozer Common Faults

Case 1450BTIP – Most Case crawlers have transmission pressure gauges – this is a valuable tool for diagnosing faults. If yours is broken, think about getting it replaced.



Q: When cold, why does my transmission not engage drive straight away?
A: Often this is due to a lack of pressure due to the transmission pump sucking air – cavitating.
Low oil level?
Check hose clamps on all suction lines
If any oil leaks are present, while machine is parked – these are usually leaks on the suction side of system & need repair.
If all clamps are tight & no leaks are present – the problem could be the charge pump itself.

Q: Why is my transmission overheating?
A: Caused by a number of reasons
1) Air flow through radiator / oil cooler restricted with dirt, grass etc.(usually effects engine temp as well)
2) Loss of oil flow due to bad pump or internal leakage at torque convertor or transmission clutch packs
3) Transmission oil being superheated by faulty clutch pack operation. eg – two being engaged at the same time (fwd & rev / low & hi on same side)

Q: Why won’t my machine engage left & right tracks at the same time?
Why is there a hesitation when I change gears/range?
A: There is a problem with internal oil leakage on the slower side. Often oil control rings on shafts are at fault. Sometimes faulty seal rings at clutch pack piston seals.

Q: Why does one track want to drive even when in neutral?
A : There is a broken plate in a clutch pack, locking it up & causing it to permanently drive.

Q: My machine has lost all drive & hydraulics!
A : Flexplate likely is broken – check inside engine bellhousing for debris.

Q: What do I look for when buying a used dozer / loader?
A: All of the above!
Get the machine to operating temperature; at an idle check each individual gear; the transmission pressure & response time should be EXACTLY the same for each selection.

21 thoughts on “Crawler Loader/Dozer Common Faults

  • I have a 1960ish Case 850 straight that I was working when I heard a rumbling mechnical noise under the seat. I immediately backed the unit out of the work area and noticed a loss of power to the right tracks. It still operates but not as before so I have left it parted until I can get an idea of what might be the problem. Any insight would be very helpful. Thanks!!

    • Hello Randy,
      My first thoughts are that a bearing has failed & this could affect gear contact & the drive performance. I would suggest you drain the transmission oil & see if there is any sign of metal contamination in the oil.
      You should also inspect the transmission suction screen as this will also show any sign of metal failure.
      If it looks ok in the transmission, drain the RH final drive & see what you find…..
      Don’t use the machine till you find the cause of the noise – as this can cause further damage & repair cost.
      Regards alrman

  • I have a 1985 Case 450c. My transmission is making a loud banging noise. I can feel the vibrations on the main forward reverse shaft when the machine is running. Would bent or broken clutch disks be a culprit? As soon as the machine is pushing a load it will run silent. I have drained the oil and no contamination. machine functions as it should. The same noise is made in forward and reverse gears. The machine sat for a couple years prior to me buying it. It seems to make a milder noise while in neutral and then intensify when engaged. Any help would be appreciated. Nobody locally seems to know anything about these machines.

    • Hello Austin,
      Usually, bent or broken clutch plates will not cause any noises as you have described.
      When you drained the oil did you look at the suction screen? This will tell you if something is failing in the transmission. Also, did you drain the two final drive oils, it is possible something could be wrong there.
      It is also possible you have worn out engine mountings, or worn driveshaft universals.


  • My blade drops sometimes.. It runs fine… Then all of sudden it loses pressure and falls down. No leak and tank is full??

    • Hello Matias,
      Thank you for your visit! 🙂

      I assume you have a dozer?
      Is this a Case Machine?
      What model is it?
      If the blade is 2 feet off the ground, how long does it take to reach the ground?

  • I have a 455C Case Loader and when operating after 15 to 20 minutes the transmission pressure builds up so high that it blew the filter and the filter housing apart. After fixing it back, I put a inline pressure gage on the filter assembly and then within 10 to 15 minutes it blew the “O” ring out of the filter and the pressure raised over 500psi.
    Is there anyway you can help and tell me what you think the problem may be?

    • Hi Chuck,
      I would first look at the relief valves located under the torque convertor housing. It is possible the one or more of the valves is sticking, causing the high pressure.
      The plungers/valve pistons should move freely in their bores.
      Cheers 🙂

  • My 1995 Case 850E Dozer’s Hydraulic control stopped working suddenly while I was logging on a steep slope, fluid was low however I filled it to the full mark the control still did nothing. The single lever control feels like it’s connected, is there an in-line control valve that could be disconnected? I don’t have a repair or maintenance manual.
    Thank you,

      • Everything else works properly, the control “T” handle and all connections to the valve unit are connected, however there is no response from any input from the handle. I have backed the machine off the hillside and it is sitting level, there are no leaks or signs of any damage?

        • The hydraulic system is fully mechanical, with no electrical or cut out valves.
          If all hydraulic movement has stopped working you will need to check if the pump (mounted to the LH side of the engine timing cover) is still turning. There is an small shaft in the adaptor housing which maybe damaged.
          If you still have some movement in the hydraulics, but no real power, the main relief valve (fitted to the Dozer control valve – input section) maybe at fault. Pressures will need to be checked with a test gauge.
          Hope this helps,

    • Hi,
      No, the charge pump will not affect the drive as you describe.
      Check –
      1) brake neutralizing valve for stickiness.
      2) mechanical failure within the transmission – crownwheel & pinion.
      3) mechanical failure in the final drive.

      Drain the oils in transmission & left final drive & look for debris….

      My money is on mechanical failure, sorry.


      Andrew Frino

  • my 1150 case dozer torque converter stops ( output shaft to the trans stops or turns very slow) when the machine gets warm.
    Temp never goes past the edge of the yelow. If i pile snow on the trans and wait 10 mins, it goes again for 15-20 mins and than the same thing,
    Pressure drops and stays low for a while then comes back up, but the machine doesn’t always move even when the pressure comes back.
    any ideas?

    • Hi EJ,
      I’m assuming you have a straight 1150 (with no letter model)
      My first thoughts are is the transmission charge pump ok? This would need to be tested with a flow meter.
      If that is ok, you would consider the torque converter to be suspect.
      There are a few things that can cause pressure loss & they are all internal problems requiring converter removal.
      Andrew Frino

    • Hi John, to be honest I can’t recall if there are plugs behind the flywheel, it’s been too long since I have looked in that area on a 504 engine. The parts book only shows 1 plug & that could be for the camshaft.
      Sorry I’m not more help to you but I’m away atm & don’t have access to any service manuals.

  • I have a case 450B, trans charge pump is pushing fluid into my engine after running 30 minutes or so, i have changed the charge pump 3 times now,

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