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D5H LGP transmission system issues

Discussion in 'Dozers' started by farmin, Apr 13, 2022.

  1. farmin

    farmin Well-Known Member

    Joined:
    Jan 30, 2012
    Messages:
    60
    Location:
    Wisconsin
    I have had this machine for 12 years, never a transmission problem besides now and then once its warm when put it in gear it just doesn't engage. Take it back to N and try again and works every time , previous owner stated same issue. ANYHOW

    While working yesterday I lost all gears at once machine will not move ill admit i was flying around in 3rd gear reverse to get some stuff done rushing. And then it just let go. Checked driveshaft, checked linkage into trans looks fine (had cover off back of trans to look at internal linkage), checked pressures at back of trans and no pressure at all on P1, P2 didn't go any further checking pressures. I have recently changed trans fluid, cleaned screens, changed filter. Im thinking its the charge pump? What are chances i wrecked a bunch of other stuff? How can i test charge pump output? thanks!

    Machine is 1989 d5h lgp serial 1DD1003
     

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  2. Vetech63

    Vetech63 Senior Member

    Joined:
    Aug 10, 2016
    Messages:
    4,546
    Location:
    Oklahoma
    The best and most reliable way is to use a flow meter.........that will tell you if your pump is still capable of flow and pressure availability. I am going to assume that you do not have one or access to one?
     
    mg2361 likes this.
  3. farmin

    farmin Well-Known Member

    Joined:
    Jan 30, 2012
    Messages:
    60
    Location:
    Wisconsin
    Correct I don’t. Have a neighboring mechanic I borrowed pressure gauges from could see if he does. Hate to call Cat but might have to . Wondering if running engine is hurting anything while I’m trying to test stuff.
     
  4. Nige

    Nige Senior Member

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    G..G..G..Granville.........!! Fetch your cloth.
    Can you test the transmission pump pressure somewhere on the filter housing.?
     
    Vetech63 likes this.
  5. tctractors

    tctractors Senior Member

    Joined:
    Oct 9, 2007
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    Worc U.K.
    If you have no oil pressure at P1 your pump or the Priority Valve is a knacker job, the brake pressure is the first to get oil so to check for brake seals leaking put the park brake on, still no pressure at P1 its the pump, you can pressure test at the filter it's the same as P1, the filter might only have an oil sample test port so swap it for the port from P1 or P2, remove the back cover plate and see if you have oil shooting about from the left hand side, as it might have a relief control plug for cold start over pressure stuck open or even fell out letting no pressure build up, even with a worn out pump from cold you will get some pressure at first so think of failed pump drive, to flow test a transmission pump would be a right faff I just pressure test from cold then hot and things need to be similar or less than 10% change. tctractors
     
    Nige likes this.
  6. farmin

    farmin Well-Known Member

    Joined:
    Jan 30, 2012
    Messages:
    60
    Location:
    Wisconsin
    Ok so when I open the back cover I shouldn’t see oil shooting anywhere correct? Thanks a lot to everyone. Much quicker and more helpful than dealer.