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Volvo 4400

Discussion in 'Tractor/Loader/Backhoes' started by antz, Feb 10, 2020.

  1. antz

    antz Member

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    Location:
    Aust
    I have recently purchased a BM4400 circa 1985 loader and I am having a few issues with the transmission when things warm up (20 mins of work). The transmission is reluctant to engage and when it does it is usually with a hard thud. When it does grab a gear it seems to have plenty of power, with minimal slip (will just spin the wheels). I have just replaced the trans and drop box oil and cleaned the suction filter. New oil I have put in is straight 30w about 22 litres and about 3 litres of 50w to top it up to full as I ran out of the 30w. There was some confusion with what is suitable oil, and im not sure if i have the correct stuff in there - volvo dealer here told me 10w40 and another mechanic told me straight 30w and another fella i know thought it should be 10w. I also have a transmission pressure light on when things are warm and no throttle is used. Upon initial startup the transmission behaves and shifts nicely (save for not going into 4th). The gear selector is all electronic.

    Thoughts / comments appreciated.
     
  2. funwithfuel

    funwithfuel Senior Member

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    Will county Illinois
    SAE 30 is ok if you never dip below 50 or 60F . If you have any suction leak at all, the pump is gonna have a hard time pulling oil up over air. 15w40 is what we use here in the states, it covers all your temperature ranges we would expect to see. Just make sure none of your external hoses are cracked/ sucking air.
    When time permits, I will dig a little deeper.
     
  3. funwithfuel

    funwithfuel Senior Member

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    When you say you cleaned the suction strainer, did you remove the bottom cover and physically remove it? There's an o ring on that pipe to promote a tight seal. That feeds straight up to the lube pump driven by the torque converter. Be absolutely sure that is a good seal. On the left side hidden by the shift solenoids is a lube filter canister. Filter number 4787923. That could be why your tripping the trans oil light. Aside from that, it just sounds as though it is having a hard time getting primed first thing. Lighter oil viscosity and a filter change might be just what's needed.
     
  4. antz

    antz Member

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    There is a round cover that contains the drain plug that i removed. I pulled the suction filter out and cleaned with compressed air and brake cleaner. When i reinstalled, i just pushed the pipe back where it came from. it felt like a good seal but i never checked for an oring (felt like it pushed into a seal). Does a blocked filter bypass or would it prevent flow? I have a replacement, but i hadn't found where it belongs yet.

    What external hoses are you speak of specifically? is there any way to pressure test the system?
     
    Last edited: Feb 10, 2020
  5. funwithfuel

    funwithfuel Senior Member

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    If you climb in ahead of the axle on the right side of the transmission and look forward you should see a large canister housing Below and behind the shift solenoid valve bank. That's where you are filter goes. F memory serves it's only about 1/2 bar that sense that sensor off.
     
  6. antz

    antz Member

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    ok thanks i will check it tonight. with regard to the oil, it isnt supposed to run atf was my bigger issue?
     
  7. funwithfuel

    funwithfuel Senior Member

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    You could run ATF if you were in a subzero temperature a lot, otherwise 15w40 is fine
     
  8. Paul Council

    Paul Council Senior Member

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    I suspect trash in the valve body of the transmission. If you say it takes a while to select a gear and then when it does it's pulls strong. Then I believe that you have some sort of debris in the valve body. If you have a bad pump and low pressure then it would slip. if you have a clutch pack with a blown piston seal it would be slow to engage, but it will slip. if you have changed the oil and filters and still have the same problem. Then that is where I would start looking next. I say this from experience. Had a similar problem with a zf transmission. Boss told me to pull the transmission so he can open it up and fix it. I asked him if we could pull the valve body first because that's where I thought the problem was. I only wanted to look there first because the customer said he had this problem after replacing the pressure sensor and stripped the threads. Long story short. I pulled the transmission. Boss opened it up and found nothing wrong. I then meticulously went through the valve body and found a small shard of steel in a orfice of the valve body. Put some pressure gauges on it. If you have good pressure readings then I would really suspect problems with the valve body. Good luck and I hope that this will point you in the right direction. post a serial number and I might be able to help you with more technical information about your transmission. The machine is old and I'm not sure if prosis will go back that far but I can try.
     
    funwithfuel likes this.
  9. antz

    antz Member

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    Location:
    Aust
    Ok. a few more things i will need to check. It also doesnt seem to engage 4th gear, not that i need to use it.

    Doest the fact that this only happens when it is hot rule out some issues like sucking air etc?
     

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