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955H won’t move forward or backwards

Delta211 · 2026-03-11 19:48

I have recently acquired a Cat 955H I have changed all the fluids and filters oh yeah serial # 53A8065 anyway the good news is she runs well the bad I can’t get it to move forward or backwards. It has not moved since 2008. I checked the pressure on the oil line that runs from the trans hydraulic pump to the filter housing it was 100 psi. I also checked the 2 ports on the valve body the the steering pedals hook to 0 psi. I assume that the line I got 100 psi on is a return line the book indicates it needs 300 psi to function any help would be greatly appreciated my first machine so just learning.

Replies12
  1. #1pittsburgh cat man2026-03-11 21:38

    Ah 53a makes it a 977h 1st question can you pull the gear selector in gear while its running

  2. #2Nige2026-03-11 22:18

    When you say “the book” do you have genuine Cat manuals for it or did what you have come from somewhere else.?

  3. #3Delta2112026-03-12 16:11

    Yes you can put it in any gear no restriction whatsoever and sorry 977h type O

  4. #4Delta2112026-03-12 16:13

    I have the original cat manuals service and parts

  5. #5Delta2112026-03-12 16:14

    Sorry my earlier post said 955H it is a 977H bad on my part .

  6. #6Delta2112026-03-12 16:15

    Sure hope you have a good suggestion for me I am stumped right now.

  7. #7pittsburgh cat man2026-03-12 16:48

    There is a valve on top of transmission there should be two test ports my only 53a parts book is one down from your serial number range it shows the taps to be o ring boss try to get pressures from those two taps One more thing down by the side of seat there is a lever for range transmission might try moving that

  8. #8Delta2112026-03-15 18:59

    i I have 0 psi at the 2 ports on the valve body that regular turning brake pedals are attached to?

  9. #9pittsburgh cat man2026-03-15 19:23

    This is the valve you are looking for it should be on top of the last picture

  10. #10pittsburgh cat man2026-03-15 19:27

    This is your transmission pump

  11. #11Delta2112026-03-20 13:20

    Ok thanks should it have 300 psi there?

  12. #12pittsburgh cat man2026-03-20 13:39

    One tap about 300 other about 50 pound less