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Cat D6H Transmission Pressures

Hunter013 · 2026-07-09 17:13

3YG00455 Does anyone have the locations and specs for checking any and all transmission pressures? My SIS only shows 1 diagram with a different transmission housing.

Replies15
  1. #1omarelnakeep2026-07-09 17:21

    Yes I have

  2. #2Hunter0132026-07-10 05:14

    I should rephrase that. Does anyone have the locations and specs for checking any and all transmission pressures that they’d be willing to send to me?

  3. #3Nige2026-07-10 08:54

    For some obscure reason the T&A illustration for your Serial Number shows the test points for a Direct Drive transmission not for a powershift. I have no idea why. See if the attached is any better.

  4. #4Hunter0132026-07-10 09:01

    That looks right. I have 0 psi trans lube pressure. Ive seen others have an issue with cut/missing suction line o-rings. Where do I check/access those?

  5. #5Nige2026-07-10 09:04

    Unless you are measuring it with a gauge that reads maybe 30psi max you are unlikely to see a reading. It won’t register even a flicker on a 500psi gauge. What do the other pressures look like compared to spec.?

  6. #6Hunter0132026-07-10 10:02

    I have 0 psi everywhere. Checked with several gauges. I took off the pump pressure fitting on top of the trans filter housing and nothing came out with engine on. The trans pump driveshaft is turning. Is my pump burned up?

  7. #7pittsburgh cat man2026-07-10 10:44

    Good place to start

  8. #8Hunter0132026-07-10 12:14

    Is there any other ports to check to verify pump failure? Or is pulling hoses/pump to check for shavings the next step?

  9. #9Nige2026-07-10 12:31

    Have you looked at the magnetic screen at the bottom of the rear of the transmission case yet.? Also pull the transmission filter and cut it open. Look for particles in the bottom of the pleats of the filter media.

  10. #10pittsburgh cat man2026-07-10 13:27

    I seem to remember problems with keys in shafts

  11. #11Hunter0132026-07-10 20:03

    I haven’t pulled the magnetic screen yet. I cut the filter open and it was clean. Is the shaft keyed after the rubber coupler?

  12. #12pittsburgh cat man2026-07-10 20:12

    it's actually shaft to gears inside pump

  13. #13pittsburgh cat man2026-07-10 20:18

    This might help you

  14. #14Hunter0132026-07-10 20:31

    Could a guy take off the input housing to look/fix it? Or would it be best to just remove the whole pump and disassemble on a bench?

  15. #15pittsburgh cat man2026-07-10 20:38

    I would take the pump off also look at keyway in gears