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CATT 299D XHP No Hydraulics

S.Fox · 2026-05-14 16:25

CAT0299DAJST01268 Give the information I can so maybe this will help other also if can figure it out. Lost all hydraulics while working. When it happened was moving some items with grapple and machine came to a stop. No movement forward or backward. For a minute I had a enough hydraulics to release the grapple and it lifted very slow and went down then would not raise again. Items checked and the work preformed so far. Fan not turning when engine running. Check to make sure Fan was not locked up it is good. When ahead and checked and changed hydraulic filter.( old one did not look bad. All research I did pointed to the coupler. So ordered couple and had a mechanic come out and pulled the engine. NOPE coupler was not bad changed it anyway. Also put the old coupler on the pump while engine was out and trund it. Was not free spinning had some resistance. Put all back together and tried again still nothing. Separated the two pumps. I turned the engine with a ratchet while he tried to hold the enter splins with a large screwdriver nope could not hold it. (Possibly telling me that shaft may not be broke) turned the back shaft with pliers and had some resistance and did not feel broke. Myself and the mechanic are both lost need some help.

Replies27
  1. #1HarleyHappy2026-05-15 12:24

    I would assume you have checked the hydraulic lock out solenoids. What if any pilot pressure and is there a pilot return filter?

  2. #2Nige2026-05-15 12:35

    Have you checked for anything electrical/electronic related.? Post a photo of the dash panel in the upper RH corner of the cab. You may be lucky and find that you can access Diagnostic Codes without ET.

  3. #3S.Fox2026-05-20 20:17
  4. #4S.Fox2026-05-20 20:19

    No have not really looked into a lot of electrical because of no warnings or codes that came up and everything i have read said the fan runs when you start it no matter what unless you have hydraulic issues. (Coupler) which it is not that.

  5. #5AMBMike2026-05-20 21:05

    Did it stop suddenly like the parking brake applied or slowly lose hydraulics and stop?

  6. #6S.Fox2026-05-20 21:08

    It just stops the hydraulics on the grapple still worked but very slow for just a few seconds long enough for me to lift and drop the log and then lowered it then would not move.

  7. #7Nige2026-05-21 12:07

    OK, so you have the Advanced Display. If you get into the service menu does it show anything for Logged Events and/or Logged Diagnostic Codes. Have you cut open the hydraulic filter to look for particles.? Is the emergency lowering handle in the correct place.? If nothing shows from any of the above then maybe it's time to break out the pressure gauges.

  8. #8Nige2026-05-21 12:15

    So if I understand you correctly the implement hydraulics don't stop completely, they just operate very slowly. What about the drive function F->R. Does it work OK.?

  9. #9S.Fox2026-05-22 05:57

    Not nothing works now. When it first stop moving the grapple moved slowly for just a few seconds now no movement on anything. No real evidence of a lot of metal in the filter that would suggest massive failure. I will check on the codes but I am leaning towards the gear pump. It supplies hydraulic fluid to everything the hydrostatic pump and work tool pump

  10. #10Nige2026-05-22 16:33

    That doesn't sound too convincing. There shouldn't be anything at all.

  11. #11Nige2026-05-22 16:41

    Try this for testing the implement relief valve.

  12. #12S.Fox2026-05-27 11:09

    Would have to get the tooling from the mechanic. I do have a question these test require you to disengage the parking brake but the fan runs on hydraulics without the brake disengage. So if there is no fan running and no fluid coming to the hydraulic filter is this test necessary?

  13. #13Nige2026-05-27 12:30

    That would be the hydraulic accumulator discharging. I did ask earlier about the emergency lowering valve position but I don't see any reply. The handle is on the rear firewall of the cab.

  14. #14S.Fox2026-05-27 15:45

    the T handle is in the down or pushes in position

  15. #15pittsburgh cat man2026-05-27 16:25

    I would be interested in what the charge pressure is

  16. #16S.Fox2026-05-27 17:11
  17. #17cat262c2026-06-28 19:24

    Hi did you figure out the problem with your cat losing all Hydraulics? I'm having the same issue on my 262C

  18. #18Nige2026-06-29 03:30

    Does the fan turn when you start the engine.?

  19. #19cat262c2026-06-30 13:14

    i don't see the fan running..

  20. #20Nige2026-06-30 13:27

    In that case I would say that it is highly likely (most likely in fact) the coupling between the engine and the pump stack has failed. Post a machine Serial Number and I'll find a parts illustration for you.

  21. #21cat262c2026-06-30 13:35

    thats what i was thinking also.. Serial-CAT0262CCMST00261 Thanks for the Help..

  22. #22Nige2026-06-30 14:48

    Well apart from the person who started this thread (who unfortunately never came back to update us on what the actual problem was on his machine) I know of no other case of a machine with no drive, implements, or fan where the cause was NOT something related to the coupling. You need Ref #2 on the attachment. While you have everything apart check the splined connector on the drive pump. Sometimes the bolt #3 can come loose and the connector #5 slides away from the coupler. Unsurprisingly this also results in no drive, implements, or fan.

  23. #23Simon C2026-06-30 23:21

    Maybe he will reappear with the end repair, but many have slipped away as into the night and never came back. Simon C

  24. #24Chrisso2026-07-01 00:39

    Same here. But after hearing that, from now on I’ll keep a broken charge pump in the back of my mind next time I come across it. How good are these forums

  25. #25cat262c2026-07-01 04:13

    Thank you! i will keep you posted on what i find..

  26. #26Jeffc19642026-08-12 18:21

    I still haven’t fixed my 279c skid steer it stopped traveling forward and reverse and my boom hydraulic would still work but after replacing a coil and cartridge and reconnected the battery I started getting a caution light flashing and now I have no boom movement and still not coming out of park I replaced the rocker switch for the park brake and checked all inner locks and next thing is to load it up and haul it to my local dealer did you ever get yours fixed

  27. #27Simon C2026-08-12 19:11

    Why not post a picture of the warning light with maybe a possible solution to follow. Might be an idea to post another thread with " Cat 279C No Forward Reverse " and post your serial number, hours on the machine and everything else that has been done and changed. Do you have a schematic for the machine. More info gets better results back. Simon C