Komatsu FG25ST-16:
Transmission Whine

Hey guys. I have a FG25ST-16 with a horrible whine coming from the transmission. The lift does drive forward and reverse but at times seems to hesitate a little. I tried checking pressures but haven't found any info on what ports test what. The port on top in the middle of the trans case that takes an allen wrench shows a pressure of 150psi but fluctuates around 10psi. I tapped into the same style port by the trans filter and got no reading at all. I see a few other very small ports in the case but have no idea what at these show if anything.
Does anyone have any insight into this?
  • Posted 11 Feb 2022 07:17
  • Discussion started by LCNIII
  • North Carolina, United States
Showing items 1 - 4 of 4 results.
I apologize for the long response time. Thanks for the help. Changing the strainer inside of the transmission worked.
  • Posted 2 Apr 2022 01:46
  • Reply by LCNIII
  • North Carolina, United States
No problem after you are done sometimes it takes a few minutes to act OK because it is dry at control valve hope l was of help
  • Posted 12 Feb 2022 00:49
  • Reply by Scott_
  • Pennsylvania, United States
Thanks for the reply. I pulled the internal filter out and I believe you are correct about it being clogged. It looks bad and weighs considerably more than I think a good one should. I'm getting one ordered and I'll fill you n on the results.
  • Posted 12 Feb 2022 00:20
  • Reply by LCNIII
  • North Carolina, United States
I read your post l will help you fix this this was a problem when the truck had hi hour readings on it.on the right side of the transmission there is a platewith appox 6bolts holding it on drain transmission first than remove bolts take plate off on bottom you will see a filter it has a hole in center you need to take a needle nose plyers and pull filter out of transmission this is the internal filter it is clogged this is why you here the noise from the transmission you need to get new filter and gasket for plate install filter and new gasket on plate and put back refill transmission note if you let go and not change you will burn up transmission it is starving for oil as for pressure reading pump pressure is180psi at1800@rpms forward pressure is 170 psi at 1800rpms same for reverse hope this helps
  • Posted 11 Feb 2022 13:11
  • Reply by Scott_
  • Pennsylvania, United States

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