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PS54810 CAT 120K prefix: JAP

PABFER.UY · 2026-02-05 18:26

Dear all, I hope you are well. I'd like to know if anyone has the service card PS54810, as it's no longer available in the SIS system. I'd like to know specifically what the problem was, as I have a motor grader with the prefix in the title, and the forward gears 2, 6, and 7, and reverse gear 2.5, aren't working. I've measured all the solenoid valves, and they all read 10 Ω.

Replies8
  1. #1Nige2026-02-05 20:01

    Clutch #4 has failed, or is not engaging. What have you checked so far.? Clutch material in screens, etc, etc.?

  2. #2PABFER.UY2026-02-06 06:56

    Good morning, I only checked the coil resistances, but it seems the gears are sticking. When I engage the problematic gears, the machine tries to move and then stops. It works perfectly in the other gears. I'm not sure where to connect a pressure gauge.

  3. #3Nige2026-02-06 09:08

    Let's start with a few basic checks. Take a good look at the transmission oil condition. Does it have a dark & cloudy or clear & bright appearance.? Does it smell burned.? Next step is to remove and inspect the transmission oil suction screen. Follow the instructions in Steps 11-17 of the attachment but do not discard any material you find in the screen or adhering to the magnets. Take a photo of it and post it up. Report back with your results.

  4. #4PABFER.UY2026-02-11 16:21

    Good afternoon everyone, in short, the transmission is practically dead, or at least clutch packs 6 and 8. I removed the transmission filter and found a lot of dirt (pieces that looked like plastic), which I understood to be remnants of friction discs. I also noticed that the transmission software was outdated, and there's an update that reduces the clutch engagement time for the clutch packs. Most likely, this whole problem was caused by the incorrect software, leading to premature wear of the discs. Or perhaps they were already very worn; the motor grader is about to reach 14,000 operating hours.

  5. #5Nige2026-02-11 17:59

    If the transmission has never been overhauled before then it is probably just worn out. Be warned it will require a LOT of cleaning internally, especially the passages inside the clutch shafts that feed oil to the pistons. Also there is a passage the feeds oil through an orifice to the balance piston for #7 clutch that often gets blocked. I need to look at any mechanical updates that might apply to that transmission in addition to any software upgrades. What is the machine Serial Number so I can check for updates.?

  6. #6Nige2026-02-11 21:58

    If it is an early Serial Number in the JAP-prefix machine range there is an updated transmission oil filter assembly available to improve oil filtration plus updated clutch pistons with a changed profile to improve piston seal life.

  7. #7PABFER.UY2026-02-12 06:58

    JAP06838

  8. #8Nige2026-02-12 09:37

    In that case both of the two updates I posted above apply, unless they have already been applied already.